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2 | // ******************************************************************** |
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24 | // ******************************************************************** |
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25 | // |
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26 | // $Id: G4He3EvaporationProbability.cc,v 1.18 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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28 | // |
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29 | // J.M. Quesada (August2008). Based on: |
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30 | // |
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31 | // Hadronic Process: Nuclear De-excitations |
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32 | // by V. Lara (Oct 1998) |
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33 | // |
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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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37 | |
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38 | #include "G4He3EvaporationProbability.hh" |
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39 | |
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40 | G4He3EvaporationProbability::G4He3EvaporationProbability() : |
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41 | G4EvaporationProbability(3,2,2,&theCoulombBarrier) // A,Z,Gamma,&theCoulombBarrier |
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42 | {} |
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43 | |
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44 | G4He3EvaporationProbability::~G4He3EvaporationProbability() |
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45 | {} |
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46 | |
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47 | G4double G4He3EvaporationProbability::CalcAlphaParam(const G4Fragment & fragment) |
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48 | { return 1.0 + CCoeficient(fragment.GetZ_asInt()-GetZ());} |
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49 | |
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50 | G4double G4He3EvaporationProbability::CalcBetaParam(const G4Fragment & ) |
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51 | { return 0.0; } |
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52 | |
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53 | |
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54 | G4double G4He3EvaporationProbability::CCoeficient(G4int aZ) |
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55 | { |
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56 | // Data comes from |
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57 | // Dostrovsky, Fraenkel and Friedlander |
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58 | // Physical Review, vol 116, num. 3 1959 |
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59 | // |
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60 | // const G4int size = 5; |
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61 | // G4double Zlist[5] = { 10.0, 20.0, 30.0, 50.0, 70.0}; |
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62 | // G4double Calpha[5] = { 0.10, 0.10, 0.10, 0.08, 0.06}; |
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63 | // C for He3 is equal to C for alpha times 4/3 |
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64 | G4double C = 0.0; |
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65 | |
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66 | if (aZ <= 30) |
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67 | { |
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68 | C = 0.10; |
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69 | } |
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70 | else if (aZ <= 50) |
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71 | { |
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72 | C = 0.1 - (aZ - 30)*0.001; |
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73 | } |
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74 | else if (aZ < 70) |
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75 | { |
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76 | C = 0.08 - (aZ - 50)*0.001; |
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77 | } |
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78 | else |
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79 | { |
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80 | C = 0.06; |
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81 | } |
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82 | return C*(4.0/3.0); |
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83 | } |
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84 | |
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85 | /////////////////////////////////////////////////////////////////////////////////// |
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86 | //J. M. Quesada (Dec 2007-June 2008): New inverse reaction cross sections |
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87 | //OPT=0 Dostrovski's parameterization |
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88 | //OPT=1,2 Chatterjee's paramaterization |
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89 | //OPT=3,4 Kalbach's parameterization |
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90 | // |
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91 | G4double |
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92 | G4He3EvaporationProbability::CrossSection(const G4Fragment & fragment, G4double K) |
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93 | { |
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94 | |
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95 | theA=GetA(); |
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96 | theZ=GetZ(); |
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97 | ResidualA=fragment.GetA_asInt()-theA; |
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98 | ResidualZ=fragment.GetZ_asInt()-theZ; |
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99 | |
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100 | ResidualAthrd=fG4pow->Z13(ResidualA); |
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101 | FragmentA=fragment.GetA_asInt(); |
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102 | FragmentAthrd=fG4pow->Z13(FragmentA); |
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103 | |
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104 | if (OPTxs==0) {std::ostringstream errOs; |
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105 | errOs << "We should'n be here (OPT =0) at evaporation cross section calculation (He3's)!!" |
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106 | <<G4endl; |
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107 | throw G4HadronicException(__FILE__, __LINE__, errOs.str()); |
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108 | return 0.;} |
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109 | if( OPTxs==1 || OPTxs==2) return G4He3EvaporationProbability::GetOpt12( K); |
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110 | else if (OPTxs==3 || OPTxs==4) return G4He3EvaporationProbability::GetOpt34( K); |
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111 | else{ |
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112 | std::ostringstream errOs; |
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113 | errOs << "BAD He3's CROSS SECTION OPTION AT EVAPORATION!!" <<G4endl; |
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114 | throw G4HadronicException(__FILE__, __LINE__, errOs.str()); |
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115 | return 0.; |
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116 | } |
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117 | } |
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118 | |
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119 | //********************* OPT=1,2 : Chatterjee's cross section ***************** |
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120 | //(fitting to cross section from Bechetti & Greenles OM potential) |
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121 | |
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122 | G4double G4He3EvaporationProbability::GetOpt12(const G4double K) |
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123 | { |
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124 | G4double Kc = K; |
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125 | |
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126 | // JMQ xsec is set constat above limit of validity |
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127 | if (K > 50*MeV) { Kc = 50*MeV; } |
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128 | |
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129 | G4double landa ,mu ,nu ,p , Ec,q,r,ji,xs; |
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130 | |
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131 | G4double p0 = -3.06; |
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132 | G4double p1 = 278.5; |
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133 | G4double p2 = -1389.; |
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134 | G4double landa0 = -0.00535; |
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135 | G4double landa1 = -11.16; |
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136 | G4double mu0 = 555.5; |
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137 | G4double mu1 = 0.40; |
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138 | G4double nu0 = 687.4; |
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139 | G4double nu1 = -476.3; |
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140 | G4double nu2 = 0.509; |
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141 | G4double delta=1.2; |
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142 | |
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143 | Ec = 1.44*theZ*ResidualZ/(1.5*ResidualAthrd+delta); |
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144 | p = p0 + p1/Ec + p2/(Ec*Ec); |
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145 | landa = landa0*ResidualA + landa1; |
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146 | |
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147 | G4double resmu1 = fG4pow->powZ(ResidualA,mu1); |
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148 | mu = mu0*resmu1; |
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149 | nu = resmu1*(nu0 + nu1*Ec + nu2*(Ec*Ec)); |
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150 | q = landa - nu/(Ec*Ec) - 2*p*Ec; |
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151 | r = mu + 2*nu/Ec + p*(Ec*Ec); |
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152 | |
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153 | ji=std::max(Kc,Ec); |
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154 | if(Kc < Ec) { xs = p*Kc*Kc + q*Kc + r;} |
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155 | else {xs = p*(Kc - ji)*(Kc - ji) + landa*Kc + mu + nu*(2 - Kc/ji)/ji ;} |
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156 | |
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157 | if (xs <0.0) {xs=0.0;} |
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158 | |
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159 | return xs; |
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160 | |
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161 | } |
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162 | |
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163 | // *********** OPT=3,4 : Kalbach's cross sections (from PRECO code)************* |
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164 | G4double G4He3EvaporationProbability::GetOpt34(const G4double K) |
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165 | //c ** 3he from o.m. of gibson et al |
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166 | { |
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167 | G4double landa, mu, nu, p , signor(1.),sig; |
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168 | G4double ec,ecsq,xnulam,etest(0.),a; |
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169 | G4double b,ecut,cut,ecut2,geom,elab; |
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170 | |
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171 | G4double flow = 1.e-18; |
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172 | G4double spill= 1.e+18; |
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173 | |
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174 | G4double p0 = -2.88; |
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175 | G4double p1 = 205.6; |
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176 | G4double p2 = -1487.; |
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177 | G4double landa0 = 0.00459; |
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178 | G4double landa1 = -8.93; |
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179 | G4double mu0 = 611.2; |
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180 | G4double mu1 = 0.35; |
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181 | G4double nu0 = 473.8; |
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182 | G4double nu1 = -468.2; |
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183 | G4double nu2 = -2.225; |
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184 | |
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185 | G4double ra=0.80; |
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186 | |
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187 | //JMQ 13/02/09 increase of reduced radius to lower the barrier |
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188 | // ec = 1.44 * theZ * ResidualZ / (1.5*ResidualAthrd+ra); |
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189 | ec = 1.44 * theZ * ResidualZ / (1.7*ResidualAthrd+ra); |
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190 | ecsq = ec * ec; |
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191 | p = p0 + p1/ec + p2/ecsq; |
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192 | landa = landa0*ResidualA + landa1; |
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193 | a = fG4pow->powZ(ResidualA,mu1); |
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194 | mu = mu0 * a; |
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195 | nu = a* (nu0+nu1*ec+nu2*ecsq); |
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196 | xnulam = nu / landa; |
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197 | if (xnulam > spill) { xnulam=0.; } |
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198 | if (xnulam >= flow) { etest = 1.2 *std::sqrt(xnulam); } |
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199 | |
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200 | a = -2.*p*ec + landa - nu/ecsq; |
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201 | b = p*ecsq + mu + 2.*nu/ec; |
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202 | ecut = 0.; |
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203 | cut = a*a - 4.*p*b; |
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204 | if (cut > 0.) ecut = std::sqrt(cut); |
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205 | ecut = (ecut-a) / (p+p); |
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206 | ecut2 = ecut; |
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207 | //JMQ 290310 for avoiding unphysical increase below minimum (at ecut) |
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208 | // ecut<0 means that there is no cut with energy axis, i.e. xs is set |
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209 | // to 0 bellow minimum |
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210 | // if (cut < 0.) ecut2 = ecut - 2.; |
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211 | if (cut < 0.) { ecut2 = ecut; } |
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212 | elab = K * FragmentA /G4double(ResidualA); |
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213 | sig = 0.; |
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214 | |
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215 | if (elab <= ec) { //start for E<Ec |
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216 | if (elab > ecut2) { sig = (p*elab*elab+a*elab+b) * signor; } |
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217 | } //end for E<Ec |
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218 | else { //start for E>Ec |
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219 | sig = (landa*elab+mu+nu/elab) * signor; |
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220 | geom = 0.; |
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221 | if (xnulam < flow || elab < etest) { return sig; } |
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222 | geom = std::sqrt(theA*K); |
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223 | geom = 1.23*ResidualAthrd + ra + 4.573/geom; |
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224 | geom = 31.416 * geom * geom; |
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225 | sig = std::max(geom,sig); |
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226 | } //end for E>Ec |
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227 | return sig; |
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228 | |
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229 | } |
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