[819] | 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 7 | // * conditions of the Geant4 Software License, included in the file * |
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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| 9 | // * include a list of copyright holders. * |
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| 10 | // * * |
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| 11 | // * Neither the authors of this software system, nor their employing * |
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| 12 | // * institutes,nor the agencies providing financial support for this * |
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| 13 | // * work make any representation or warranty, express or implied, * |
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| 14 | // * regarding this software system or assume any liability for its * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 16 | // * for the full disclaimer and the limitation of liability. * |
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| 17 | // * * |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 19 | // * technical work of the GEANT4 collaboration. * |
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| 20 | // * By using, copying, modifying or distributing the software (or * |
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| 21 | // * any work based on the software) you agree to acknowledge its * |
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| 22 | // * use in resulting scientific publications, and indicate your * |
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| 23 | // * acceptance of all terms of the Geant4 Software license. * |
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| 24 | // ******************************************************************** |
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| 25 | // |
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| 26 | // |
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| 27 | // $Id: G4NeutronHPMadlandNixSpectrum.hh,v 1.12 2006/06/29 20:48:33 gunter Exp $ |
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| 28 | // GEANT4 tag $Name: $ |
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| 29 | // |
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| 30 | #ifndef G4NeutronHPMadlandNixSpectrum_h |
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| 31 | #define G4NeutronHPMadlandNixSpectrum_h 1 |
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| 32 | |
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| 33 | #include "globals.hh" |
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| 34 | #include "G4NeutronHPVector.hh" |
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| 35 | #include "Randomize.hh" |
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| 36 | #include "G4ios.hh" |
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| 37 | #include <fstream> |
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| 38 | #include <cmath> |
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| 39 | #include "G4VNeutronHPEDis.hh" |
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| 40 | |
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| 41 | // #include <nag.h> @ |
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| 42 | // #include <nags.h> @ |
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| 43 | |
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| 44 | |
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| 45 | // we will need a List of these .... one per term. |
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| 46 | |
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| 47 | class G4NeutronHPMadlandNixSpectrum : public G4VNeutronHPEDis |
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| 48 | { |
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| 49 | public: |
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| 50 | G4NeutronHPMadlandNixSpectrum() |
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| 51 | { |
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| 52 | expm1 = std::exp(-1.); |
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| 53 | } |
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| 54 | ~G4NeutronHPMadlandNixSpectrum() |
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| 55 | { |
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| 56 | } |
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| 57 | |
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| 58 | inline void Init(std::ifstream & aDataFile) |
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| 59 | { |
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| 60 | theFractionalProb.Init(aDataFile); |
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| 61 | aDataFile>> theAvarageKineticPerNucleonForLightFragments; |
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| 62 | theAvarageKineticPerNucleonForLightFragments*=eV; |
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| 63 | aDataFile>> theAvarageKineticPerNucleonForHeavyFragments; |
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| 64 | theAvarageKineticPerNucleonForHeavyFragments*=eV; |
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| 65 | theMaxTemp.Init(aDataFile); |
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| 66 | } |
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| 67 | |
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| 68 | inline G4double GetFractionalProbability(G4double anEnergy) |
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| 69 | { |
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| 70 | return theFractionalProb.GetY(anEnergy); |
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| 71 | } |
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| 72 | |
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| 73 | G4double Sample(G4double anEnergy); |
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| 74 | |
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| 75 | private: |
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| 76 | |
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| 77 | G4double Madland(G4double aSecEnergy, G4double tm); |
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| 78 | |
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| 79 | inline G4double FissionIntegral(G4double tm, G4double anEnergy) |
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| 80 | { |
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| 81 | return 0.5*( GIntegral(tm, anEnergy, theAvarageKineticPerNucleonForLightFragments) |
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| 82 | +GIntegral(tm, anEnergy, theAvarageKineticPerNucleonForHeavyFragments) ); |
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| 83 | } |
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| 84 | |
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| 85 | G4double GIntegral(G4double tm, G4double anEnergy, G4double aMean); |
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| 86 | |
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| 87 | inline G4double Gamma05(G4double aValue) |
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| 88 | { |
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| 89 | G4double result; |
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| 90 | // gamma(1.2,x*X) = std::sqrt(pi)*Erf(x) |
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| 91 | G4double x = std::sqrt(aValue); |
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| 92 | G4double t = 1./(1+0.47047*x); |
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| 93 | result = 1- (0.3480242*t - 0.0958798*t*t + 0.7478556*t*t*t)*std::exp(-aValue); // @ check |
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| 94 | result *= std::sqrt(pi); |
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| 95 | return result; |
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| 96 | } |
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| 97 | |
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| 98 | inline G4double Gamma15(G4double aValue) |
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| 99 | { |
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| 100 | G4double result; |
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| 101 | // gamma(a+1, x) = a*gamma(a,x)-x**a*std::exp(-x) |
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| 102 | result = 0.5*Gamma05(aValue) - std::sqrt(aValue)*std::exp(-aValue); // @ check |
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| 103 | return result; |
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| 104 | } |
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| 105 | |
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| 106 | inline G4double Gamma25(G4double aValue) |
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| 107 | { |
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| 108 | G4double result; |
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| 109 | result = 1.5*Gamma15(aValue) - std::pow(aValue,1.5)*std::exp(aValue); // @ check |
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| 110 | return result; |
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| 111 | } |
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| 112 | |
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| 113 | inline G4double E1(G4double aValue) |
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| 114 | { |
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| 115 | // good only for rather low aValue @@@ replace by the corresponding NAG function for the |
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| 116 | // exponential integral. (<5 seems ok. |
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| 117 | G4double gamma = 0.577216; |
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| 118 | G4double precision = 0.000001; |
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| 119 | G4double result =-gamma - std::log(aValue); |
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| 120 | G4double term = -aValue; |
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| 121 | G4double last; |
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| 122 | G4int count = 1; |
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| 123 | result -= term; |
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| 124 | for(;;) |
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| 125 | { |
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| 126 | count++; |
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| 127 | last = result; |
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| 128 | term = -term*aValue*(count-1)/(count*count); |
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| 129 | result -=term; |
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| 130 | if(std::fabs(term)/std::fabs(result)<precision) break; |
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| 131 | } |
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| 132 | // NagError *fail; @ |
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| 133 | // result = nag_exp_integral(aValue, fail); @ |
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| 134 | return result; |
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| 135 | } |
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| 136 | |
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| 137 | private: |
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| 138 | |
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| 139 | G4double expm1; |
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| 140 | |
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| 141 | private: |
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| 142 | |
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| 143 | G4NeutronHPVector theFractionalProb; |
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| 144 | |
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| 145 | G4double theAvarageKineticPerNucleonForLightFragments; |
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| 146 | G4double theAvarageKineticPerNucleonForHeavyFragments; |
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| 147 | |
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| 148 | G4NeutronHPVector theMaxTemp; |
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| 149 | |
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| 150 | }; |
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| 151 | |
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| 152 | #endif |
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