Gabriele Cosmo
113 lines
4.3 KiB
C++
113 lines
4.3 KiB
C++
//
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// ********************************************************************
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// * DISCLAIMER *
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// * *
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// * The following disclaimer summarizes all the specific disclaimers *
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// * of contributors to this software. The specific disclaimers,which *
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// * govern, are listed with their locations in: *
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// * http://cern.ch/geant4/license *
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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. *
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// * *
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// * This code implementation is the intellectual property of the *
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// * GEANT4 collaboration. *
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// * By copying, distributing or modifying the Program (or any work *
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// * based on the Program) you indicate your acceptance of this *
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// * statement, and all its terms. *
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// ********************************************************************
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//
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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: G4PhotoElectricAngularGeneratorStandard
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//
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// Creation date: 10 May 2004
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//
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// Modifications:
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// 10 May 2003 P. Rodrigues First implementation acording with new design
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//
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// Class Description:
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//
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// Concrete class for PhotoElectric Electron Angular Distribution Generation
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// This model is a re-implementation of the Photolectric angular distribution
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// developed my M. Maire for the Standard EM Physics G4PhotoElectricEffect
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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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//
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#include "G4PhotoElectricAngularGeneratorStandard.hh"
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#include "Randomize.hh"
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//
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G4PhotoElectricAngularGeneratorStandard::G4PhotoElectricAngularGeneratorStandard(const G4String& name):G4VPhotoElectricAngularDistribution(name)
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{;}
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//
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G4PhotoElectricAngularGeneratorStandard::~G4PhotoElectricAngularGeneratorStandard()
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{;}
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//
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G4ThreeVector G4PhotoElectricAngularGeneratorStandard::GetPhotoElectronDirection(G4ThreeVector direction, G4double eKineticEnergy)
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{
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// Compute Theta distribution of the emitted electron, with respect to the
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// incident Gamma.
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// The Sauter-Gavrila distribution for the K-shell is used. (adapted from G4PhotoElectricEffect)
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G4double costeta = 1.;
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G4double Phi = twopi * G4UniformRand();
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G4double cosphi = std::cos(Phi);
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G4double sinphi = std::sin(Phi);
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G4double sinteta = 0;
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G4double gamma = 1. + eKineticEnergy/electron_mass_c2;
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if (gamma > 5.) {
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G4ThreeVector direction (sinteta*cosphi, sinteta*sinphi, costeta);
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return costeta;
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}
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G4double beta = std::sqrt(gamma*gamma-1.)/gamma;
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G4double b = 0.5*gamma*(gamma-1.)*(gamma-2);
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G4double rndm,term,greject,grejsup;
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if (gamma < 2.) grejsup = gamma*gamma*(1.+b-beta*b);
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else grejsup = gamma*gamma*(1.+b+beta*b);
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do { rndm = 1.-2*G4UniformRand();
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costeta = (rndm+beta)/(rndm*beta+1.);
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term = 1.-beta*costeta;
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greject = (1.-costeta*costeta)*(1.+b*term)/(term*term);
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} while(greject < G4UniformRand()*grejsup);
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sinteta = std::sqrt(1.-costeta*costeta);
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G4ThreeVector photoelectrondirection (sinteta*cosphi, sinteta*sinphi, costeta);
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photoelectrondirection.rotateUz(direction);
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return photoelectrondirection;
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}
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//
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void G4PhotoElectricAngularGeneratorStandard::PrintGeneratorInformation() const
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{
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G4cout << "\n" << G4endl;
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G4cout << "" << G4endl;
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G4cout << "Re-implementation of the photolectric angular distribution" << G4endl;
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G4cout << "developed my M. Maire for the Standard EM Physics G4PhotoElectricEffect" << G4endl;
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G4cout << "It computes the theta distribution of the emitted electron, with respect to the" << G4endl;
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G4cout << "incident Gamma, using the Sauter-Gavrila distribution for the K-shell\n" << G4endl;
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}
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