| 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: G4FissionBarrier.cc,v 1.8 2010/11/17 20:22:46 vnivanch Exp $ |
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| 28 | // GEANT4 tag $Name: geant4-09-04-ref-00 $ |
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| 29 | // |
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| 30 | // Hadronic Process: Nuclear De-excitations |
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| 31 | // by V. Lara (Oct 1998) |
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| 32 | // |
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| 33 | // 17.11.2010 V.Ivanchenko cleanup and add usage of G4Pow |
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| 34 | |
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| 35 | #include "G4FissionBarrier.hh" |
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| 36 | #include "G4Pow.hh" |
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| 37 | |
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| 38 | G4FissionBarrier::G4FissionBarrier() |
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| 39 | {} |
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| 40 | |
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| 41 | G4FissionBarrier::~G4FissionBarrier() |
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| 42 | {} |
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| 43 | |
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| 44 | G4double |
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| 45 | G4FissionBarrier::FissionBarrier(G4int A, G4int Z, G4double U) |
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| 46 | // Compute fission barrier according with Barashenkov's |
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| 47 | // prescription for A >= 65 |
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| 48 | { |
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| 49 | if (A >= 65) { |
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| 50 | return BarashenkovFissionBarrier(A,Z)/(1.0 + std::sqrt(U/(2.0*A))); |
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| 51 | } else { return 100.0*GeV; } |
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| 52 | } |
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| 53 | |
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| 54 | G4double |
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| 55 | G4FissionBarrier::BarashenkovFissionBarrier(G4int A, G4int Z) |
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| 56 | // Calculates Fission Barrier heights |
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| 57 | { |
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| 58 | // Liquid drop model parameters for |
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| 59 | // surface energy of a spherical nucleus |
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| 60 | const G4double aSurf = 17.9439*MeV; |
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| 61 | // and coulomb energy |
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| 62 | const G4double aCoul = 0.7053*MeV; |
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| 63 | const G4double k = 1.7826; |
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| 64 | G4int N = A - Z; |
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| 65 | |
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| 66 | // fissibility parameter |
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| 67 | G4double x = (aCoul/(2.0*aSurf))*(Z*Z)/static_cast<G4double>(A); |
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| 68 | x /= (1.0 - k*(N-Z)*(N-Z)/static_cast<G4double>(A*A)); |
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| 69 | |
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| 70 | // Liquid drop model part of Fission Barrier |
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| 71 | G4double BF0 = aSurf*G4Pow::GetInstance()->Z23(A); |
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| 72 | if (x <= 2./3.) { BF0 *= 0.38*(3./4.-x); } |
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| 73 | else { BF0 *= 0.83*(1. - x)*(1. - x)*(1. - x); } |
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| 74 | |
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| 75 | // |
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| 76 | G4double D = 1.248*MeV; |
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| 77 | D *= (N - 2*(N/2) + Z - 2*(Z/2)); |
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| 78 | |
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| 79 | return BF0 + D - SellPlusPairingCorrection(Z,N); |
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| 80 | } |
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| 81 | |
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