Gabriele Cosmo
97 lines
2.8 KiB
C++
97 lines
2.8 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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//
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#include "globals.hh"
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#include "G4BetaFermiFunction.hh"
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const G4double G4BetaFermiFunction::PI=3.14159;
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//////////////////////////////////////////////////////////////////
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//
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// calculate the Fermi Function foe energy E0
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//
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G4double G4BetaFermiFunction::GetFF( const G4double E0)
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{
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G4double A1, A2;
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G4double P, U, S, Y;
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G4double F2;
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G4double E = E0+1.;
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P=std::sqrt(E*E-1.0) ;
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U=Z/137.0;
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S=std::sqrt(1.0-U*U) - 1.;
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Y = 2*PI*U*E/P;
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A1 = U*U*E*E + P*P/4.;
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A2 = std::fabs(Y/(1-std::exp(-Y)));
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F2 = std::pow(A1,S) * A2;
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return F2;
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}
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//////////////////////////////////////////////////////////////////
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//
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// calculate the Fermi normalization factor
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// here E0 is the end point energy of the beta decay
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//
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G4double G4BetaFermiFunction::GetFFN(const G4double E0)
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{
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G4double A1, A2;
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G4double P, U, S, Y;
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G4double F2,E;
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G4double EE = E0/100.;
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U=Z/137.0;
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S=std::sqrt(1.0-U*U) - 1.;
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G4double F1 = 1E-10;
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for (G4int i = 1; i<=100 ; i++) {
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E = G4double(i)*EE + 1.;
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P=std::sqrt(E*E-1.0) ;
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Y = 2*PI*U*E/P;
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A1 = U*U*E*E + P*P/4.;
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A2 = std::fabs(Y/(1-std::exp(-Y)));
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F2 = std::pow(A1,S) * A2;
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if (F2 > F1) F1 = F2;
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}
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return F1;
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}
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