Gabriele Cosmo
90 lines
3.6 KiB
C++
90 lines
3.6 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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//
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// Hadronic Process: Nuclear De-excitations
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// by V. Lara (Oct 1998)
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//
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//
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// J.M.Quesada (14 february 2009) bug fixed in fission width: missing
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// parenthesis in the denominator
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#include "G4FissionProbability.hh"
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#include "G4PhysicalConstants.hh"
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#include "G4NuclearLevelData.hh"
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#include "G4PairingCorrection.hh"
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#include "G4EvaporationLevelDensityParameter.hh"
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#include "G4FissionLevelDensityParameter.hh"
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#include "G4Exp.hh"
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G4FissionProbability::G4FissionProbability() :
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G4VEmissionProbability(0, 0),
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theEvapLDP(new G4EvaporationLevelDensityParameter),
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theFissLDP(new G4FissionLevelDensityParameter),
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ownEvapLDP(true),
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ownFissLDP(true)
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{
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fPairCorr = G4NuclearLevelData::GetInstance()->GetPairingCorrection();
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}
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G4FissionProbability::~G4FissionProbability()
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{
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if (ownEvapLDP) delete theEvapLDP;
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if (ownFissLDP) delete theFissLDP;
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}
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G4double
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G4FissionProbability::EmissionProbability(const G4Fragment & fragment,
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G4double MaximalKineticEnergy)
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// Compute integrated probability of fission channel
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{
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if (MaximalKineticEnergy <= 0.0) { return 0.0; }
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G4int A = fragment.GetA_asInt();
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G4int Z = fragment.GetZ_asInt();
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G4double U = fragment.GetExcitationEnergy();
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G4double Ucompound = U - fPairCorr->GetPairingCorrection(A,Z);
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G4double Ufission = U - fPairCorr->GetFissionPairingCorrection(A,Z);
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if(Ucompound < 0.0 || Ufission < 0.0) { return 0.0; }
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G4double SystemEntropy =
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2.0*std::sqrt(theEvapLDP->LevelDensityParameter(A,Z,Ucompound)*Ucompound);
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G4double afission = theFissLDP->LevelDensityParameter(A,Z,Ufission);
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G4double Cf = 2.0*std::sqrt(afission*MaximalKineticEnergy);
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G4double Exp1 = (SystemEntropy <= 160.0) ? G4Exp(-SystemEntropy) : 0.0;
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G4double Exp2 = (SystemEntropy-Cf <= 160.0) ? G4Exp(-SystemEntropy+Cf) : 0.0;
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// JMQ 14/02/09 BUG fixed in fission probability (missing parenthesis
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// at denominator)
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G4double probability = (Exp1 + (Cf-1.0)*Exp2) / (4.0*pi*afission);
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return probability;
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}
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