Gabriele Cosmo
104 lines
3.7 KiB
C++
104 lines
3.7 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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//
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// P. Arce, June-2014 Conversion neutron_hp to particle_hp
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//
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#ifndef G4ParticleHPFissionSpectrum_h
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#define G4ParticleHPFissionSpectrum_h 1
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#include "G4Exp.hh"
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#include "G4ParticleHPVector.hh"
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#include "G4VParticleHPEDis.hh"
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#include "G4ios.hh"
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#include "Randomize.hh"
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#include "globals.hh"
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#include <CLHEP/Units/SystemOfUnits.h>
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#include <fstream>
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// we will need a List of these .... one per term.
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class G4ParticleHPFissionSpectrum : public G4VParticleHPEDis
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{
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public:
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G4ParticleHPFissionSpectrum() { expm1 = G4Exp(-1.); }
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~G4ParticleHPFissionSpectrum() override = default;
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inline void Init(std::istream& aDataFile) override
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{
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theFractionalProb.Init(aDataFile, CLHEP::eV);
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theThetaDist.Init(aDataFile, CLHEP::eV);
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}
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inline G4double GetFractionalProbability(G4double anEnergy) override
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{
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return theFractionalProb.GetY(anEnergy);
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}
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inline G4double Sample(G4double anEnergy) override
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{
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G4double theta = theThetaDist.GetY(anEnergy);
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// here we need to sample Maxwells distribution, if
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// need be.
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G4double result = 0., cut;
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G4double range = 50 * CLHEP::MeV;
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G4double max = Maxwell((theta * CLHEP::eV) / 2., theta);
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G4double value;
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G4int icounter = 0;
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G4int icounter_max = 1024;
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do {
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icounter++;
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if (icounter > icounter_max) {
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G4cout << "Loop-counter exceeded the threshold value at " << __LINE__ << "th line of "
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<< __FILE__ << "." << G4endl;
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break;
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}
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result = range * G4UniformRand();
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value = Maxwell(result, theta);
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cut = G4UniformRand();
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} while (cut > value / max); // Loop checking, 11.05.2015, T. Koi
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return result;
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}
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private:
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// this is the function to sample from.
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inline G4double Maxwell(G4double anEnergy, G4double theta)
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{
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G4double result = std::sqrt(anEnergy / CLHEP::eV) * G4Exp(-anEnergy / CLHEP::eV / theta);
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return result;
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}
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private:
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G4double expm1;
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G4ParticleHPVector theFractionalProb;
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G4ParticleHPVector theThetaDist;
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};
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#endif
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