[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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[1347] | 26 | // $Id: G4NeutronEvaporationProbability.cc,v 1.16 2010/11/17 11:06:03 vnivanch Exp $ |
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| 27 | // GEANT4 tag $Name: geant4-09-04-ref-00 $ |
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[819] | 28 | // |
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[1347] | 29 | // J.M. Quesada (August2008). Based on: |
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| 30 | // |
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[819] | 31 | // Hadronic Process: Nuclear De-excitations |
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[962] | 32 | // by V. Lara (Oct 1998) |
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[819] | 33 | // |
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[1347] | 34 | // Modified: |
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| 35 | // 03-09-2008 J.M. Quesada for external choice of inverse cross section option |
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| 36 | // 17-11-2010 V.Ivanchenko integer Z and A |
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[819] | 37 | |
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| 38 | #include "G4NeutronEvaporationProbability.hh" |
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| 39 | |
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| 40 | G4NeutronEvaporationProbability::G4NeutronEvaporationProbability() : |
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[962] | 41 | G4EvaporationProbability(1,0,2,&theCoulombBarrier) // A,Z,Gamma,&theCoulombBarrier |
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[1347] | 42 | {} |
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[819] | 43 | |
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[1347] | 44 | G4NeutronEvaporationProbability::~G4NeutronEvaporationProbability() |
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| 45 | {} |
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[819] | 46 | |
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[1347] | 47 | G4double G4NeutronEvaporationProbability::CalcAlphaParam(const G4Fragment & fragment) |
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| 48 | { |
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| 49 | return 0.76+2.2/fG4pow->Z13(fragment.GetA_asInt()-GetA()); |
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[819] | 50 | } |
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[1347] | 51 | |
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| 52 | G4double G4NeutronEvaporationProbability::CalcBetaParam(const G4Fragment & fragment) |
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| 53 | { |
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| 54 | return (2.12/fG4pow->Z23(fragment.GetA_asInt()-GetA()) - 0.05)*MeV/ |
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| 55 | CalcAlphaParam(fragment); |
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[819] | 56 | } |
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| 57 | |
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[962] | 58 | //////////////////////////////////////////////////////////////////////////////////// |
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| 59 | //J. M. Quesada (Dec 2007-June 2008): New inverse reaction cross sections |
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| 60 | //OPT=0 Dostrovski's parameterization |
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| 61 | //OPT=1,2 Chatterjee's paramaterization |
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| 62 | //OPT=3,4 Kalbach's parameterization |
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| 63 | // |
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[1347] | 64 | G4double |
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| 65 | G4NeutronEvaporationProbability::CrossSection(const G4Fragment & fragment, G4double K) |
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[962] | 66 | { |
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| 67 | theA=GetA(); |
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| 68 | theZ=GetZ(); |
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[1347] | 69 | ResidualA=fragment.GetA_asInt()-theA; |
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| 70 | ResidualZ=fragment.GetZ_asInt()-theZ; |
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| 71 | |
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| 72 | ResidualAthrd=fG4pow->Z13(ResidualA); |
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| 73 | FragmentA=fragment.GetA_asInt(); |
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| 74 | FragmentAthrd=fG4pow->Z13(FragmentA); |
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[962] | 75 | |
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| 76 | if (OPTxs==0) {std::ostringstream errOs; |
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| 77 | errOs << "We should'n be here (OPT =0) at evaporation cross section calculation (neutrons)!!" <<G4endl; |
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| 78 | throw G4HadronicException(__FILE__, __LINE__, errOs.str()); |
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| 79 | return 0.;} |
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| 80 | else if( OPTxs==1 ||OPTxs==2) return GetOpt12( K); |
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| 81 | else if (OPTxs==3 || OPTxs==4) return GetOpt34( K); |
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| 82 | else{ |
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| 83 | std::ostringstream errOs; |
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| 84 | errOs << "BAD NEUTRON CROSS SECTION OPTION AT EVAPORATION!!" <<G4endl; |
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| 85 | throw G4HadronicException(__FILE__, __LINE__, errOs.str()); |
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| 86 | return 0.; |
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| 87 | } |
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| 88 | } |
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[1347] | 89 | |
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| 90 | //********************* OPT=1,2 : Chatterjee's cross section *************** |
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[962] | 91 | //(fitting to cross section from Bechetti & Greenles OM potential) |
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| 92 | |
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[1347] | 93 | G4double G4NeutronEvaporationProbability::GetOpt12(G4double K) |
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[962] | 94 | { |
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| 95 | G4double Kc=K; |
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| 96 | |
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[1347] | 97 | // Pramana (Bechetti & Greenles) for neutrons is chosen |
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[962] | 98 | |
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[1347] | 99 | // JMQ xsec is set constat above limit of validity |
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| 100 | if (K > 50*MeV) { Kc = 50*MeV; } |
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| 101 | |
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[962] | 102 | G4double landa, landa0, landa1, mu, mu0, mu1,nu, nu0, nu1, nu2,xs; |
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| 103 | |
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| 104 | landa0 = 18.57; |
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| 105 | landa1 = -22.93; |
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| 106 | mu0 = 381.7; |
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| 107 | mu1 = 24.31; |
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| 108 | nu0 = 0.172; |
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| 109 | nu1 = -15.39; |
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| 110 | nu2 = 804.8; |
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| 111 | landa = landa0/ResidualAthrd + landa1; |
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| 112 | mu = mu0*ResidualAthrd + mu1*ResidualAthrd*ResidualAthrd; |
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| 113 | nu = nu0*ResidualAthrd*ResidualA + nu1*ResidualAthrd*ResidualAthrd + nu2 ; |
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| 114 | xs=landa*Kc + mu + nu/Kc; |
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| 115 | if (xs <= 0.0 ){ |
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| 116 | std::ostringstream errOs; |
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| 117 | G4cout<<"WARNING: NEGATIVE OPT=1 neutron cross section "<<G4endl; |
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| 118 | errOs << "RESIDUAL: Ar=" << ResidualA << " Zr=" << ResidualZ <<G4endl; |
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| 119 | errOs <<" xsec("<<Kc<<" MeV) ="<<xs <<G4endl; |
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| 120 | throw G4HadronicException(__FILE__, __LINE__, errOs.str()); |
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[1347] | 121 | } |
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[962] | 122 | return xs; |
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| 123 | } |
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| 124 | |
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| 125 | // *********** OPT=3,4 : Kalbach's cross sections (from PRECO code)************* |
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[1347] | 126 | G4double G4NeutronEvaporationProbability::GetOpt34(G4double K) |
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[962] | 127 | { |
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| 128 | G4double landa, landa0, landa1, mu, mu0, mu1,nu, nu0, nu1, nu2; |
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| 129 | G4double p, p0, p1, p2; |
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| 130 | G4double flow,spill,ec,ecsq,xnulam,etest(0.),ra(0.),a,signor(1.),sig; |
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| 131 | G4double b,ecut,cut,ecut2,geom,elab; |
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| 132 | |
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[1347] | 133 | //safety initialization |
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[962] | 134 | landa0=0; |
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| 135 | landa1=0; |
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| 136 | mu0=0.; |
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| 137 | mu1=0.; |
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| 138 | nu0=0.; |
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| 139 | nu1=0.; |
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| 140 | nu2=0.; |
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| 141 | p0=0.; |
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| 142 | p1=0.; |
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| 143 | p2=0.; |
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| 144 | |
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| 145 | flow = 1.e-18; |
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| 146 | spill= 1.0e+18; |
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| 147 | |
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[1347] | 148 | // PRECO xs for neutrons is choosen |
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[962] | 149 | p0 = -312.; |
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| 150 | p1= 0.; |
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| 151 | p2 = 0.; |
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| 152 | landa0 = 12.10; |
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| 153 | landa1= -11.27; |
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| 154 | mu0 = 234.1; |
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| 155 | mu1 = 38.26; |
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| 156 | nu0 = 1.55; |
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| 157 | nu1 = -106.1; |
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| 158 | nu2 = 1280.8; |
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| 159 | |
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[1347] | 160 | if (ResidualA < 40) { signor =0.7 + ResidualA*0.0075; } |
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| 161 | if (ResidualA > 210) { signor = 1. + (ResidualA-210)/250.; } |
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[962] | 162 | landa = landa0/ResidualAthrd + landa1; |
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| 163 | mu = mu0*ResidualAthrd + mu1*ResidualAthrd*ResidualAthrd; |
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| 164 | nu = nu0*ResidualAthrd*ResidualA + nu1*ResidualAthrd*ResidualAthrd + nu2; |
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| 165 | |
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| 166 | // JMQ very low energy behaviour corrected (problem for A (apprx.)>60) |
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[1347] | 167 | if (nu < 0.) { nu=-nu; } |
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[962] | 168 | |
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| 169 | ec = 0.5; |
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| 170 | ecsq = 0.25; |
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| 171 | p = p0; |
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| 172 | xnulam = 1.; |
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| 173 | etest = 32.; |
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[1347] | 174 | // ** etest is the energy above which the rxn cross section is |
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| 175 | // ** compared with the geometrical limit and the max taken. |
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| 176 | // ** xnulam here is a dummy value to be used later. |
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[962] | 177 | |
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| 178 | a = -2.*p*ec + landa - nu/ecsq; |
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| 179 | b = p*ecsq + mu + 2.*nu/ec; |
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| 180 | ecut = 0.; |
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| 181 | cut = a*a - 4.*p*b; |
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[1347] | 182 | if (cut > 0.) { ecut = std::sqrt(cut); } |
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[962] | 183 | ecut = (ecut-a) / (p+p); |
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| 184 | ecut2 = ecut; |
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[1347] | 185 | if (cut < 0.) { ecut2 = ecut - 2.; } |
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| 186 | elab = K * FragmentA / G4double(ResidualA); |
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[962] | 187 | sig = 0.; |
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| 188 | if (elab <= ec) { //start for E<Ec |
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[1347] | 189 | if (elab > ecut2) { sig = (p*elab*elab+a*elab+b) * signor; } |
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[962] | 190 | } //end for E<Ec |
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| 191 | else { //start for E>Ec |
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| 192 | sig = (landa*elab+mu+nu/elab) * signor; |
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| 193 | geom = 0.; |
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[1347] | 194 | if (xnulam < flow || elab < etest) { return sig; } |
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[962] | 195 | geom = std::sqrt(theA*K); |
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| 196 | geom = 1.23*ResidualAthrd + ra + 4.573/geom; |
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| 197 | geom = 31.416 * geom * geom; |
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| 198 | sig = std::max(geom,sig); |
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[1347] | 199 | |
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[962] | 200 | } |
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[1347] | 201 | return sig; |
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| 202 | } |
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[962] | 203 | |
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