Gabriele Cosmo
150 lines
4.5 KiB
C++
150 lines
4.5 KiB
C++
//
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// ********************************************************************
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// * DISCLAIMER *
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// * *
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// * The following disclaimer summarizes all the specific disclaimers *
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// * of contributors to this software. The specific disclaimers,which *
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// * govern, are listed with their locations in: *
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// * http://cern.ch/geant4/license *
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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. *
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// * *
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// * This code implementation is the intellectual property of the *
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// * GEANT4 collaboration. *
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// * By copying, distributing or modifying the Program (or any work *
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// * based on the Program) you indicate your acceptance of this *
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// * statement, and all its terms. *
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// ********************************************************************
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//
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//
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// $Id: G4NeutronHPMadlandNixSpectrum.hh,v 1.7 2002/12/12 19:18:14 gunter Exp $
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// GEANT4 tag $Name: geant4-05-00 $
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//
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#ifndef G4NeutronHPMadlandNixSpectrum_h
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#define G4NeutronHPMadlandNixSpectrum_h 1
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#include "globals.hh"
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#include "G4NeutronHPVector.hh"
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#include "Randomize.hh"
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#include "G4ios.hh"
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#include "g4std/fstream"
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#include <math.h>
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#include "G4VNeutronHPEDis.hh"
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// #include <nag.h> @
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// #include <nags.h> @
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// we will need a List of these .... one per term.
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class G4NeutronHPMadlandNixSpectrum : public G4VNeutronHPEDis
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{
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public:
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G4NeutronHPMadlandNixSpectrum()
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{
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expm1 = exp(-1.);
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}
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~G4NeutronHPMadlandNixSpectrum()
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{
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}
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inline void Init(G4std::ifstream & aDataFile)
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{
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theFractionalProb.Init(aDataFile);
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aDataFile>> theAvarageKineticPerNucleonForLightFragments;
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theAvarageKineticPerNucleonForLightFragments*=eV;
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aDataFile>> theAvarageKineticPerNucleonForHeavyFragments;
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theAvarageKineticPerNucleonForHeavyFragments*=eV;
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theMaxTemp.Init(aDataFile);
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}
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inline G4double GetFractionalProbability(G4double anEnergy)
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{
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return theFractionalProb.GetY(anEnergy);
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}
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G4double Sample(G4double anEnergy);
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private:
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G4double Madland(G4double aSecEnergy, G4double tm);
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inline G4double FissionIntegral(G4double tm, G4double anEnergy)
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{
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return 0.5*( GIntegral(tm, anEnergy, theAvarageKineticPerNucleonForLightFragments)
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+GIntegral(tm, anEnergy, theAvarageKineticPerNucleonForHeavyFragments) );
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}
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G4double GIntegral(G4double tm, G4double anEnergy, G4double aMean);
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inline G4double Gamma05(G4double aValue)
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{
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G4double result;
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// gamma(1.2,x*X) = sqrt(pi)*Erf(x)
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G4double x = sqrt(aValue);
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G4double t = 1./(1+0.47047*x);
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result = 1- (0.3480242*t - 0.0958798*t*t + 0.7478556*t*t*t)*exp(-aValue); // @ check
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result *= sqrt(pi);
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return result;
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}
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inline G4double Gamma15(G4double aValue)
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{
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G4double result;
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// gamma(a+1, x) = a*gamma(a,x)-x**a*exp(-x)
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result = 0.5*Gamma05(aValue) - sqrt(aValue)*exp(-aValue); // @ check
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return result;
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}
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inline G4double Gamma25(G4double aValue)
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{
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G4double result;
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result = 1.5*Gamma15(aValue) - pow(aValue,1.5)*exp(aValue); // @ check
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return result;
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}
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inline G4double E1(G4double aValue)
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{
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// good only for rather low aValue @@@ replace by the corresponding NAG function for the
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// exponential integral. (<5 seems ok.
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G4double gamma = 0.577216;
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G4double precision = 0.000001;
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G4double result =-gamma - log(aValue);
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G4double term = -aValue;
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G4double last;
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G4int count = 1;
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result -= term;
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for(;;)
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{
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count++;
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last = result;
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term = -term*aValue*(count-1)/(count*count);
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result -=term;
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if(fabs(term)/fabs(result)<precision) break;
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}
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// NagError *fail; @
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// result = nag_exp_integral(aValue, fail); @
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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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private:
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G4NeutronHPVector theFractionalProb;
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G4double theAvarageKineticPerNucleonForLightFragments;
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G4double theAvarageKineticPerNucleonForHeavyFragments;
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G4NeutronHPVector theMaxTemp;
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};
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#endif
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