Gabriele Cosmo
86 lines
1.9 KiB
C++
86 lines
1.9 KiB
C++
// This code implementation is the intellectual property of
|
|
// neutron_hp -- header file
|
|
// J.P. Wellisch, Nov-1996
|
|
// A prototype of the low energy neutron transport model.
|
|
//
|
|
// By copying, distributing or modifying the Program (or any work
|
|
// based on the Program) you indicate your acceptance of this statement,
|
|
// and all its terms.
|
|
//
|
|
// $Id: G4NeutronHPFissionSpectrum.hh,v 1.4 1999/12/15 14:53:12 gunter Exp $
|
|
// GEANT4 tag $Name: geant4-03-00 $
|
|
//
|
|
#ifndef G4NeutronHPFissionSpectrum_h
|
|
#define G4NeutronHPFissionSpectrum_h 1
|
|
|
|
#include "globals.hh"
|
|
#include "G4NeutronHPVector.hh"
|
|
#include "Randomize.hh"
|
|
#include "G4ios.hh"
|
|
#include "g4std/fstream"
|
|
#include "G4VNeutronHPEDis.hh"
|
|
|
|
// we will need a List of these .... one per term.
|
|
|
|
class G4NeutronHPFissionSpectrum : public G4VNeutronHPEDis
|
|
{
|
|
public:
|
|
G4NeutronHPFissionSpectrum()
|
|
{
|
|
expm1 = exp(-1.);
|
|
}
|
|
~G4NeutronHPFissionSpectrum()
|
|
{
|
|
}
|
|
|
|
inline void Init(G4std::ifstream & aDataFile)
|
|
{
|
|
theFractionalProb.Init(aDataFile, eV);
|
|
theThetaDist.Init(aDataFile, eV);
|
|
}
|
|
|
|
inline G4double GetFractionalProbability(G4double anEnergy)
|
|
{
|
|
return theFractionalProb.GetY(anEnergy);
|
|
}
|
|
|
|
inline G4double Sample(G4double anEnergy)
|
|
{
|
|
G4double theta = theThetaDist.GetY(anEnergy);
|
|
// here we need to sample Maxwells distribution, if
|
|
// need be.
|
|
G4double result, cut;
|
|
G4double range =50*MeV;
|
|
G4double max = Maxwell((theta*eV)/2., theta);
|
|
G4double value;
|
|
do
|
|
{
|
|
result = range*G4UniformRand();
|
|
value = Maxwell(result, theta);
|
|
cut = G4UniformRand();
|
|
}
|
|
while(cut > value/max);
|
|
return result;
|
|
}
|
|
|
|
private:
|
|
|
|
// this is the function to sample from.
|
|
inline G4double Maxwell(G4double anEnergy, G4double theta)
|
|
{
|
|
G4double result = sqrt(anEnergy/eV)*exp(-anEnergy/eV/theta);
|
|
return result;
|
|
}
|
|
|
|
private:
|
|
|
|
G4double expm1;
|
|
|
|
G4NeutronHPVector theFractionalProb;
|
|
|
|
G4NeutronHPVector theThetaDist;
|
|
|
|
};
|
|
|
|
#endif
|