[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 | // neutron_hp -- source file |
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| 27 | // J.P. Wellisch, Nov-1996 |
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| 28 | // A prototype of the low energy neutron transport model. |
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| 29 | // |
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[962] | 30 | // 080801 Protect div0 error, when theCompundFraction is 1 by T. Koi |
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| 31 | // |
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[819] | 32 | #include "G4NeutronHPKallbachMannSyst.hh" |
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| 33 | #include "Randomize.hh" |
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| 34 | #include "G4HadronicException.hh" |
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| 35 | |
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| 36 | G4double G4NeutronHPKallbachMannSyst::Sample(G4double anEnergy) |
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| 37 | { |
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| 38 | G4double result; |
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| 39 | |
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| 40 | G4double zero = GetKallbachZero(anEnergy); |
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| 41 | if(zero>1) zero=1.; |
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| 42 | if(zero<-1)zero=-1.; |
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| 43 | G4double max = Kallbach(zero, anEnergy); |
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| 44 | double upper = Kallbach(1., anEnergy); |
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| 45 | double lower = Kallbach(-1., anEnergy); |
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| 46 | if(upper>max) max=upper; |
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| 47 | if(lower>max) max=lower; |
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| 48 | G4double value, random; |
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| 49 | do |
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| 50 | { |
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| 51 | result = 2.*G4UniformRand()-1; |
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| 52 | value = Kallbach(result, anEnergy)/max; |
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| 53 | random = G4UniformRand(); |
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| 54 | } |
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| 55 | while(random>value); |
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| 56 | |
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| 57 | return result; |
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| 58 | } |
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| 59 | |
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| 60 | G4double G4NeutronHPKallbachMannSyst::Kallbach(G4double cosTh, G4double anEnergy) |
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| 61 | { |
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| 62 | // Kallbach-Mann systematics without normalization. |
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| 63 | G4double result; |
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| 64 | G4double theX = A(anEnergy)*cosTh; |
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| 65 | result = 0.5*(std::exp( theX)*(1+theCompoundFraction) |
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| 66 | +std::exp(-theX)*(1-theCompoundFraction)); |
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| 67 | return result; |
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| 68 | } |
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| 69 | |
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| 70 | G4double G4NeutronHPKallbachMannSyst::GetKallbachZero(G4double anEnergy) |
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| 71 | { |
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| 72 | G4double result; |
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[962] | 73 | if ( theCompoundFraction == 1 ) |
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| 74 | { |
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| 75 | //G4cout << "080730b Adjust theCompoundFraction " << G4endl; |
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| 76 | theCompoundFraction *= (1-1.0e-15); |
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| 77 | } |
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[819] | 78 | result = 0.5 * (1./A(anEnergy)) * std::log((1-theCompoundFraction)/(1+theCompoundFraction)); |
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| 79 | return result; |
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| 80 | } |
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| 81 | |
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| 82 | G4double G4NeutronHPKallbachMannSyst::A(G4double anEnergy) |
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| 83 | { |
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| 84 | G4double result; |
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| 85 | G4double C1 = 0.04/MeV; |
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| 86 | G4double C2 = 1.8E-6/(MeV*MeV*MeV); |
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| 87 | G4double C3 = 6.7E-7/(MeV*MeV*MeV*MeV); |
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| 88 | |
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| 89 | G4double epsa = anEnergy*theTargetMass/(theTargetMass+theIncidentMass); |
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| 90 | G4int Ac = theTargetA+1; |
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| 91 | G4int Nc = Ac - theTargetZ; |
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| 92 | G4int AA = theTargetA; |
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| 93 | G4int ZA = theTargetZ; |
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| 94 | G4double ea = epsa+SeparationEnergy(Ac, Nc, AA, ZA); |
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| 95 | G4double Et1 = 130*MeV; |
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| 96 | G4double R1 = std::min(ea, Et1); |
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| 97 | // theProductEnergy is still in CMS!!! |
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| 98 | G4double epsb = theProductEnergy*(theProductMass+theResidualMass)/theResidualMass; |
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| 99 | G4int AB = theResidualA; |
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| 100 | G4int ZB = theResidualZ; |
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| 101 | G4double eb = epsb+SeparationEnergy(Ac, Nc, AB, ZB ); |
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| 102 | G4double X1 = R1*eb/ea; |
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| 103 | G4double Et3 = 41*MeV; |
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| 104 | G4double R3 = std::min(ea, Et3); |
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| 105 | G4double X3 = R3*eb/ea; |
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| 106 | G4double Ma = 1; |
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| 107 | G4double mb(0); |
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| 108 | G4int productA = theTargetA+1-theResidualA; |
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| 109 | G4int productZ = theTargetZ-theResidualZ; |
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| 110 | if(productZ==0) |
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| 111 | { |
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| 112 | mb = 0.5; |
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| 113 | } |
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| 114 | else if(productZ==1) |
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| 115 | { |
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| 116 | mb = 1; |
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| 117 | } |
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| 118 | else if(productZ==2) |
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| 119 | { |
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| 120 | mb = 2; |
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| 121 | if(productA==3) mb=1; |
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| 122 | } |
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| 123 | else |
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| 124 | { |
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| 125 | throw G4HadronicException(__FILE__, __LINE__, "Severe error in the sampling of Kallbach-Mann Systematics"); |
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| 126 | } |
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| 127 | |
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| 128 | result = C1*X1 + C2*std::pow(X1, 3.) + C3*Ma*mb*std::pow(X3, 4.); |
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| 129 | return result; |
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| 130 | } |
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| 131 | |
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| 132 | G4double G4NeutronHPKallbachMannSyst::SeparationEnergy(G4int Ac, G4int Nc, G4int AA, G4int ZA) |
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| 133 | { |
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| 134 | G4double result; |
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| 135 | G4int NA = AA-ZA; |
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| 136 | G4int Zc = Ac-Nc; |
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| 137 | result = 15.68*(Ac-AA); |
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| 138 | result += -28.07*((Nc-Zc)*(Nc-Zc)/Ac - (NA-ZA)*(NA-ZA)/AA); |
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| 139 | result += -18.56*(std::pow(G4double(Ac), 2./3.) - std::pow(G4double(AA), 2./3.)); |
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| 140 | result += 33.22*((Nc-Zc)*(Nc-Zc)/std::pow(G4double(Ac), 4./3.) - (NA-ZA)*(NA-ZA)/std::pow(G4double(AA), 4./3.)); |
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| 141 | result += -0.717*(Zc*Zc/std::pow(G4double(Ac),1./3.)-ZA*ZA/std::pow(G4double(AA),1./3.)); |
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| 142 | result += 1.211*(Zc*Zc/Ac-ZA*ZA/AA); |
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| 143 | G4double totalBinding(0); |
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| 144 | G4int productA = theTargetA+1-theResidualA; |
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| 145 | G4int productZ = theTargetZ-theResidualZ; |
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| 146 | if(productZ==0&&productA==1) totalBinding=0; |
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| 147 | if(productZ==1&&productA==1) totalBinding=0; |
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| 148 | if(productZ==1&&productA==2) totalBinding=2.22; |
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| 149 | if(productZ==1&&productA==3) totalBinding=8.48; |
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| 150 | if(productZ==2&&productA==3) totalBinding=7.72; |
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| 151 | if(productZ==2&&productA==4) totalBinding=28.3; |
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| 152 | result += -totalBinding; |
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| 153 | result *= MeV; |
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| 154 | return result; |
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| 155 | } |
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