136 lines
3.4 KiB
C++
136 lines
3.4 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: G4NeutronHPMadlandNixSpectrum.hh,v 1.3 1999/07/02 09:59:26 johna Exp $
|
|
// GEANT4 tag $Name: geant4-01-00 $
|
|
//
|
|
#ifndef G4NeutronHPMadlandNixSpectrum_h
|
|
#define G4NeutronHPMadlandNixSpectrum_h 1
|
|
|
|
#include "globals.hh"
|
|
#include "G4NeutronHPVector.hh"
|
|
#include "Randomize.hh"
|
|
#include "G4ios.hh"
|
|
#include <fstream.h>
|
|
#include <math.h>
|
|
#include "G4VNeutronHPEDis.hh"
|
|
|
|
// #include <nag.h> @
|
|
// #include <nags.h> @
|
|
|
|
|
|
// we will need a List of these .... one per term.
|
|
|
|
class G4NeutronHPMadlandNixSpectrum : public G4VNeutronHPEDis
|
|
{
|
|
public:
|
|
G4NeutronHPMadlandNixSpectrum()
|
|
{
|
|
expm1 = exp(-1.);
|
|
}
|
|
~G4NeutronHPMadlandNixSpectrum()
|
|
{
|
|
}
|
|
|
|
inline void Init(ifstream & aDataFile)
|
|
{
|
|
theFractionalProb.Init(aDataFile);
|
|
aDataFile>> theAvarageKineticPerNucleonForLightFragments;
|
|
theAvarageKineticPerNucleonForLightFragments*=eV;
|
|
aDataFile>> theAvarageKineticPerNucleonForHeavyFragments;
|
|
theAvarageKineticPerNucleonForHeavyFragments*=eV;
|
|
theMaxTemp.Init(aDataFile);
|
|
}
|
|
|
|
inline G4double GetFractionalProbability(G4double anEnergy)
|
|
{
|
|
return theFractionalProb.GetY(anEnergy);
|
|
}
|
|
|
|
G4double Sample(G4double anEnergy);
|
|
|
|
private:
|
|
|
|
G4double Madland(G4double aSecEnergy, G4double tm);
|
|
|
|
inline G4double FissionIntegral(G4double tm, G4double anEnergy)
|
|
{
|
|
return 0.5*( GIntegral(tm, anEnergy, theAvarageKineticPerNucleonForLightFragments)
|
|
+GIntegral(tm, anEnergy, theAvarageKineticPerNucleonForHeavyFragments) );
|
|
}
|
|
|
|
G4double GIntegral(G4double tm, G4double anEnergy, G4double aMean);
|
|
|
|
inline G4double Gamma05(G4double aValue)
|
|
{
|
|
G4double result;
|
|
// gamma(1.2,x*X) = sqrt(pi)*Erf(x)
|
|
G4double x = sqrt(aValue);
|
|
G4double t = 1./(1+0.47047*x);
|
|
result = 1- (0.3480242*t - 0.0958798*t*t + 0.7478556*t*t*t)*exp(-aValue); // @ check
|
|
result *= sqrt(pi);
|
|
return result;
|
|
}
|
|
|
|
inline G4double Gamma15(G4double aValue)
|
|
{
|
|
G4double result;
|
|
// gamma(a+1, x) = a*gamma(a,x)-x**a*exp(-x)
|
|
result = 0.5*Gamma05(aValue) - sqrt(aValue)*exp(-aValue); // @ check
|
|
return result;
|
|
}
|
|
|
|
inline G4double Gamma25(G4double aValue)
|
|
{
|
|
G4double result;
|
|
result = 1.5*Gamma15(aValue) - pow(aValue,1.5)*exp(aValue); // @ check
|
|
return result;
|
|
}
|
|
|
|
inline G4double E1(G4double aValue)
|
|
{
|
|
// good only for rather low aValue @@@ replace by the corresponding NAG function for the
|
|
// exponential integral. (<5 seems ok.
|
|
G4double gamma = 0.577216;
|
|
G4double precision = 0.000001;
|
|
G4double result =-gamma - log(aValue);
|
|
G4double term = -aValue;
|
|
G4double last;
|
|
G4int count = 1;
|
|
result -= term;
|
|
for(;;)
|
|
{
|
|
count++;
|
|
last = result;
|
|
term = -term*aValue*(count-1)/(count*count);
|
|
result -=term;
|
|
if(fabs(term)/fabs(result)<precision) break;
|
|
}
|
|
// NagError *fail; @
|
|
// result = nag_exp_integral(aValue, fail); @
|
|
return result;
|
|
}
|
|
|
|
private:
|
|
|
|
G4double expm1;
|
|
|
|
private:
|
|
|
|
G4NeutronHPVector theFractionalProb;
|
|
|
|
G4double theAvarageKineticPerNucleonForLightFragments;
|
|
G4double theAvarageKineticPerNucleonForHeavyFragments;
|
|
|
|
G4NeutronHPVector theMaxTemp;
|
|
|
|
};
|
|
|
|
#endif
|