G4ParticleHPSimpleEvapSpectrum.hh

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// P. Arce, June-2014 Conversion neutron_hp to particle_hp
//
#ifndef G4ParticleHPSimpleEvapSpectrum_h
#define G4ParticleHPSimpleEvapSpectrum_h 1
 
#include "G4Exp.hh"
#include "G4Log.hh"
#include "G4ParticleHPVector.hh"
#include "G4VParticleHPEDis.hh"
#include "G4ios.hh"
#include "Randomize.hh"
#include "globals.hh"
 
#include <CLHEP/Units/SystemOfUnits.h>
 
#include <fstream>
 
// we will need a List of these .... one per term.
 
class G4ParticleHPSimpleEvapSpectrum : public G4VParticleHPEDis
{
  public:
    G4ParticleHPSimpleEvapSpectrum() { expm1 = G4Exp(-1.); }
    ~G4ParticleHPSimpleEvapSpectrum() override = default;
 
    inline void Init(std::istream& aDataFile) override
    {
      theFractionalProb.Init(aDataFile, CLHEP::eV);
      theThetaDist.Init(aDataFile, CLHEP::eV);
    }
 
    inline G4double GetFractionalProbability(G4double anEnergy) override
    {
      return theFractionalProb.GetY(anEnergy);
    }
 
    inline G4double Sample(G4double anEnergy) override
    {
      G4double theta = theThetaDist.GetY(anEnergy) * CLHEP::eV;
      G4double random, cut, max, result = 0.;
      max = 10. * theta;
      G4int icounter = 0;
      G4int icounter_max = 1024;
      do {
        icounter++;
        if (icounter > icounter_max) {
          G4cout << "Loop-counter exceeded the threshold value at " << __LINE__ << "th line of "
                 << __FILE__ << "." << G4endl;
          break;
        }
        random = G4UniformRand();
        result = -theta * G4Log(random);
        cut = G4UniformRand();
      } while (cut > result / max);  // Loop checking, 11.05.2015, T. Koi
      return result;
    }
 
  private:
    inline G4double Evapo(G4double anEnergy, G4double theta)
    {
      G4double result = (anEnergy * CLHEP::eV) * G4Exp(-anEnergy * CLHEP::eV / theta);
      return result;
    }
 
  private:
    G4double expm1;
 
    G4ParticleHPVector theFractionalProb;
 
    G4ParticleHPVector theThetaDist;
};
 
#endif