Gabriele Cosmo
182 lines
6.7 KiB
C++
182 lines
6.7 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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// Implementation of the HETC88 code into Geant4.
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// Evaporation and De-excitation parts
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// T. Lampen, Helsinki Institute of Physics, May-2000
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//
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// 20120608 M. Kelsey -- Change vars 's','m','m2' to avoid name collisions
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#include "G4BEChargedChannel.hh"
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#include "G4SystemOfUnits.hh"
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G4BEChargedChannel::G4BEChargedChannel()
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{
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verboseLevel = 0;
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}
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G4BEChargedChannel::~G4BEChargedChannel()
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{
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}
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void G4BEChargedChannel::calculateProbability()
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{
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G4int residualZ = nucleusZ - particleZ;
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G4int residualA = nucleusA - particleA;
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// Check if nucleus is too small, if this evaporation channel
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// leads to an impossible residual nucleus or if there is no enough
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// energy.
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if ( nucleusA < 2.0 * particleA ||
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nucleusZ < 2.0 * particleZ ||
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residualA <= residualZ ||
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excitationEnergy - getThresh() - correction < 0 )
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{
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if ( verboseLevel >= 6 )
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G4cout << "G4BEChargedChannel : calculateProbability for " << getName() << " = 0 " << G4endl;
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emissionProbability = 0;
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return;
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}
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// In HETC88 s-s0 was used in std::exp( s ), in which s0 was either 50 or
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// max(s_i), where i goes over all channels.
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G4double levelParam = getLevelDensityParameter();
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G4double slevel = 2 * std::sqrt( levelParam * ( excitationEnergy - getThresh() - correction ) );
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G4double constant = A / 2 * ( 2 * spin + 1 ) * ( 1 + coulombFactor() );
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G4double eye1 = ( slevel*slevel - 3 * slevel + 3 ) / ( 4 * levelParam*levelParam ) * std::exp( slevel );
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emissionProbability = constant * std::pow( G4double(residualA), 0.6666666 ) * eye1;
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if ( verboseLevel >= 6 )
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G4cout << "G4BEChargedChannel : calculateProbability for " << getName() << G4endl
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<< " res A = " << residualA << G4endl
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<< " res Z = " << residualZ << G4endl
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<< " c*(c_i+1) = "<< constant << G4endl
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<< " qmfactor = "<< qmFactor() << G4endl
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<< " coulombfactor = "<< coulombFactor() << G4endl
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<< " E = " << excitationEnergy << G4endl
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<< " correction = " << correction << G4endl
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<< " eye1 = " << eye1 << G4endl
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<< " levelParam = " << levelParam << G4endl
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<< " thresh = " << getThresh() << G4endl
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<< " s = " << s << G4endl
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<< " probability = " << emissionProbability << G4endl;
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return;
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}
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G4double G4BEChargedChannel::sampleKineticEnergy()
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{
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G4double levelParam;
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levelParam = getLevelDensityParameter();
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const G4double xMax = excitationEnergy - getThresh() - correction; // maximum number
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const G4double xProb = ( - 1 + std::sqrt ( 1 + 4 * levelParam * xMax ) ) / ( 2 * levelParam ); // most probable value
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const G4double maxProb = xProb * std::exp ( 2 * std::sqrt ( levelParam * ( xMax - xProb ) ) ); // maximum value of P(x)
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// Sample x according to density function P(x) with rejection method
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G4double r1;
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G4double r2;
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G4int koe=0;
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do
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{
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r1 = G4UniformRand() * xMax;
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r2 = G4UniformRand() * maxProb;
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koe++;
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}
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while ( r1 * std::exp ( 2 * std::sqrt ( levelParam * ( xMax - r1 ) ) ) < r2 );
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// G4cout << "Q ch " << koe << G4endl;
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G4double kineticEnergy = r1 + getCoulomb(); // add coulomb potential;
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if ( verboseLevel >= 10 )
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G4cout << " G4BENeutronChannel : sampleKineticEnergy() " << G4endl
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<< " kinetic n e = " << kineticEnergy << G4endl
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<< " levelParam = " << levelParam << G4endl
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<< " thresh= " << getThresh() << G4endl;
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return kineticEnergy;
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}
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G4double G4BEChargedChannel::coulombFactorForProton()
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{
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// Coefficient c_p:s for empirical cross section formula are
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// defined with the proton constant. See Dostrovsky, Phys. Rev.,
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// vol. 116, 1959.
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G4double t[7] = { 0.08 , 0 , -0.06 , -0.1 , -0.1 , -0.1 , -0.1 };
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G4int Z = nucleusZ - particleZ;
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if ( Z >= 70.0 ) return t[6];
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if ( Z <= 10.0 ) return t[0];
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// Linear interpolation
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G4int n = G4int( 0.1 * Z + 1.0 );
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G4float x = ( 10 * n - Z ) * 0.1;
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G4double ret_val = x * t[n - 2] + ( 1.0 - x ) * t[n-1];
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return ret_val;
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}
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G4double G4BEChargedChannel::qmFactorForProton()
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{
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// Coefficient k_p for empirical cross section formula are defined
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// with the proton constant. See Dostrovsky, Phys. Rev., vol. 116,
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// 1959
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G4double t[7] = { 0.36, 0.51, 0.60, 0.66, 0.68, 0.69, 0.69 };
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G4int Z = nucleusZ - particleZ;
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if ( Z >= 70.0 ) return t[6];
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if ( Z <= 10.0 ) return t[0];
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// Linear interpolation
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G4int n = G4int( 0.1 * Z + 1.0 );
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G4float x = ( 10 * n - Z ) * 0.1;
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return x * t[n - 2] + ( 1.0 - x ) * t[n-1];
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}
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G4double G4BEChargedChannel::qmFactorForAlpha()
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{
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// Coefficient k_alpha for empirical cross section formula presented
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// in Dostrovsky, Phys. Rev., vol. 116, 1959
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G4double t[7] = { 0.77, 0.81, 0.85, 0.89, 0.93, 0.97, 1.00 };
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G4int Z = nucleusZ - particleZ;
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if ( Z >= 70.0 ) return t[6];
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if ( Z <= 10.0 ) return t[0];
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// Linear interpolation
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G4int n = G4int( 0.1 * Z + 1.0 );
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G4float x = ( 10 * n - Z ) * 0.1;
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return x * t[n - 2] + ( 1.0 - x ) * t[n-1];
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}
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