Gabriele Cosmo
145 lines
5.3 KiB
C++
145 lines
5.3 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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// $Id: G4Generator2BS.cc,v 1.10 2010-10-14 14:01:02 vnivanch Exp $
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// GEANT4 tag $Name: not supported by cvs2svn $
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//
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// -------------------------------------------------------------------
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//
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// GEANT4 Class file
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//
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//
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// File name: G4Generator2BS
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//
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// Author: Andreia Trindade (andreia@lip.pt)
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// Pedro Rodrigues (psilva@lip.pt)
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// Luis Peralta (luis@lip.pt)
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//
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// Creation date: 2 June 2003
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//
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// Modifications:
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// 02 Jun 2003 First implementation acording with new design
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// 05 Nov 2003 MGP Fixed std namespace
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// 17 Nov 2003 MGP Fixed compilation problem on Windows
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// 12 Oct 2010 V.Ivanchenko Moved RejectionFunction inline, use G4Pow to speadup
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// 09 May 2011 L.Pandola Initialize private members, to avoid Coverity warning
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//
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// Class Description:
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//
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// Concrete base class for Bremsstrahlung Angular Distribution Generation
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// 2BS Distribution
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//
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// Class Description: End
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//
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// -------------------------------------------------------------------
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//
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#include "G4Generator2BS.hh"
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#include "Randomize.hh"
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#include "G4Pow.hh"
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//
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G4Generator2BS::G4Generator2BS(const G4String&)
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: G4VBremAngularDistribution("AngularGen2BS"),z(1),rejection_argument1(0),
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rejection_argument2(0),rejection_argument3(0),EnergyRatio(1)
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{
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g4pow = G4Pow::GetInstance();
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}
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//
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G4Generator2BS::~G4Generator2BS()
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{}
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//
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G4double G4Generator2BS::PolarAngle(const G4double initial_energy,
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const G4double final_energy,
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const G4int Z)
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{
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// Adapted from "Improved bremsstrahlung photon angular sampling in the EGS4 code system"
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// by Alex F. Bielajew, Rahde Mohan anc Chen-Shou Chui, PIRS-0203
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// Ionizing Radiation Standards
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// Institute for National Measurement Standards
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// National Research Council of Canada
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// Departement of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York
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G4double theta = 0;
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G4double initialTotalEnergy = (initial_energy+electron_mass_c2)/electron_mass_c2;
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G4double finalTotalEnergy = (final_energy+electron_mass_c2)/electron_mass_c2;
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EnergyRatio = finalTotalEnergy/initialTotalEnergy;
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G4double gMaxEnergy = (pi*initialTotalEnergy)*(pi*initialTotalEnergy);
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//G4double Zeff = std::sqrt(static_cast<G4double>(Z) * (static_cast<G4double>(Z) + 1.0));
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//z = (0.00008116224*(std::pow(Zeff,0.3333333)));
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// VI speadup
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z = 0.00008116224*(g4pow->Z13(Z) + g4pow->Z13(Z+1));
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// Rejection arguments
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rejection_argument1 = (1.0+EnergyRatio*EnergyRatio);
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rejection_argument2 = - 2.0*EnergyRatio + 3.0*rejection_argument1;
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rejection_argument3 = ((1-EnergyRatio)/(2.0*initialTotalEnergy*EnergyRatio))*
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((1-EnergyRatio)/(2.0*initialTotalEnergy*EnergyRatio));
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// Calculate rejection function at 0, 1 and Emax
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G4double gfunction0 = RejectionFunction(0.0);
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G4double gfunction1 = RejectionFunction(1.0);
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G4double gfunctionEmax = RejectionFunction(gMaxEnergy);
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// Calculate Maximum value
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G4double gMaximum = std::max(gfunction0,gfunction1);
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gMaximum = std::max(gMaximum,gfunctionEmax);
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G4double rand, gfunctionTest, randTest;
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do{
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rand = G4UniformRand();
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rand /= (1 - rand + 1.0/gMaxEnergy);
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gfunctionTest = RejectionFunction(rand);
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randTest = G4UniformRand();
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} while(randTest*gMaximum > gfunctionTest);
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theta = std::sqrt(rand)/initialTotalEnergy;
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return theta;
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}
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//
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void G4Generator2BS::PrintGeneratorInformation() const
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{
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G4cout << "\n" << G4endl;
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G4cout << "Bremsstrahlung Angular Generator is 2BS Generator "
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<< "from 2BS Koch & Motz distribution (Rev Mod Phys 31(4), 920 (1959))" << G4endl;
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G4cout << "Sampling algorithm adapted from PIRS-0203" << G4endl;
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G4cout << "\n" << G4endl;
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}
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