Geant4 11.2.2
Toolkit for the simulation of the passage of particles through matter
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G4ParticleHPFissionSpectrum.hh
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26//
27// P. Arce, June-2014 Conversion neutron_hp to particle_hp
28//
29#ifndef G4ParticleHPFissionSpectrum_h
30#define G4ParticleHPFissionSpectrum_h 1
31
32#include "G4Exp.hh"
33#include "G4ParticleHPVector.hh"
34#include "G4VParticleHPEDis.hh"
35#include "G4ios.hh"
36#include "Randomize.hh"
37#include "globals.hh"
38
40
41#include <fstream>
42
43// we will need a List of these .... one per term.
44
46{
47 public:
49 ~G4ParticleHPFissionSpectrum() override = default;
50
51 inline void Init(std::istream& aDataFile) override
52 {
53 theFractionalProb.Init(aDataFile, CLHEP::eV);
54 theThetaDist.Init(aDataFile, CLHEP::eV);
55 }
56
57 inline G4double GetFractionalProbability(G4double anEnergy) override
58 {
59 return theFractionalProb.GetY(anEnergy);
60 }
61
62 inline G4double Sample(G4double anEnergy) override
63 {
64 G4double theta = theThetaDist.GetY(anEnergy);
65 // here we need to sample Maxwells distribution, if
66 // need be.
67 G4double result = 0., cut;
68 G4double range = 50 * CLHEP::MeV;
69 G4double max = Maxwell((theta * CLHEP::eV) / 2., theta);
70 G4double value;
71 G4int icounter = 0;
72 G4int icounter_max = 1024;
73 do {
74 icounter++;
75 if (icounter > icounter_max) {
76 G4cout << "Loop-counter exceeded the threshold value at " << __LINE__ << "th line of "
77 << __FILE__ << "." << G4endl;
78 break;
79 }
80 result = range * G4UniformRand();
81 value = Maxwell(result, theta);
82 cut = G4UniformRand();
83 } while (cut > value / max); // Loop checking, 11.05.2015, T. Koi
84 return result;
85 }
86
87 private:
88 // this is the function to sample from.
89 inline G4double Maxwell(G4double anEnergy, G4double theta)
90 {
91 G4double result = std::sqrt(anEnergy / CLHEP::eV) * G4Exp(-anEnergy / CLHEP::eV / theta);
92 return result;
93 }
94
95 private:
96 G4double expm1;
97
98 G4ParticleHPVector theFractionalProb;
99
100 G4ParticleHPVector theThetaDist;
101};
102
103#endif
G4double G4Exp(G4double initial_x)
Exponential Function double precision.
Definition G4Exp.hh:180
double G4double
Definition G4Types.hh:83
int G4int
Definition G4Types.hh:85
#define G4endl
Definition G4ios.hh:67
G4GLOB_DLL std::ostream G4cout
#define G4UniformRand()
Definition Randomize.hh:52
G4double GetFractionalProbability(G4double anEnergy) override
G4double Sample(G4double anEnergy) override
~G4ParticleHPFissionSpectrum() override=default
void Init(std::istream &aDataFile) override
G4double GetY(G4double x)
void Init(std::istream &aDataFile, G4int total, G4double ux=1., G4double uy=1.)