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G4LindhardPartition.cc
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26 /*
27  * \file electromagnetic/TestEm7/src/G4LindhardPartition.cc
28  * \brief Implementation of the G4LindhardPartition class
29  *
30  * Created by Marcus Mendenhall on 1/14/08.
31  * 2008 Vanderbilt University, Nashville, TN, USA.
32  *
33  */
34 
35 //
36 
37 #include "G4LindhardPartition.hh"
38 #include "G4Material.hh"
39 #include "G4Element.hh"
40 #include "G4PhysicalConstants.hh"
41 #include "G4SystemOfUnits.hh"
42 
43 /*
44 for a first cut, we will compute NIEL from a Lindhard-Robinson partition
45 based on the most abundant element in the material.
46 
47 this is from IEEE Trans. Nucl Science Vol. 48 No.1 February 2001 page 162++
48 Insoo Jun, "Effects of Secondary Particles on the Total Dose..."
49 and, by reference,
50 Lindhard, Nielsen, Scharff & Thompson,
51 "Integral Equations Governing Radiation Efects...",
52 Mat. Fys. Medd. Dan. Vid. Selsk. vol 33 #10, pp1-42, 1963
53 and
54 Robinson, "The dependence of radiation effects on primary recoil energy",
55 in Proc. Int. Conf. Radiation-Induced Voids in Metal,
56 Albany, NY 1972 pp. 397-439
57 def lindhard_robinson(z1, a1, z2, a2, ke):
58 el=30.724*z1*z2*math.sqrt(z1**0.6667+z2**0.6667)*(a1+a2)/a2
59 fl=0.0793*z1**0.6667*math.sqrt(z2)*(a1+a2)**1.5/
60 ((z1**0.6667+z2**0.6667)**0.75*a1**1.5*math.sqrt(a2))
61 eps=ke*(1.0/el)
62 return 1.0/(1+fl*(3.4008*eps**0.16667+0.40244*eps**0.75+eps))
63 */
64 
66 {
67  max_z = 120;
68  for(size_t i=1; i<max_z; i++) {z23[i]=std::pow((G4double)i, 2./3.);}
69 }
70 
72  G4int z1, G4double a1, const G4Material *material, G4double energy) const
73 {
74  size_t nMatElements = material->GetNumberOfElements();
75 
76  const G4double *atomDensities=material->GetVecNbOfAtomsPerVolume();
77  G4double maxdens=0.0;
78  size_t maxindex=0;
79  for (size_t k=0 ; k < nMatElements ; k++ )
80  {
81  if(atomDensities[k] > maxdens) {
82  maxdens=atomDensities[k];
83  maxindex=k;
84  }
85  }
86  const G4Element *element=material->GetElement(maxindex);
87 
88  G4int z2=G4int(element->GetZ());
89 
90  G4double a2=element->GetA()/(Avogadro*amu);
91 
92  G4double zpow=z23[z1]+z23[z2];
93  G4double asum=a1+a2;
94 
95  G4double el=30.724*z1*z2*std::sqrt(zpow)*asum/a2;
96  G4double fl=0.0793*z23[z1]*std::sqrt(z2*asum*asum*asum/(a1*a1*a1*a2))
97  /std::pow(zpow, 0.75);
98  G4double eps=(energy/eV)*(1.0/el);
99 
100  return
101  1.0/(1+fl*(3.4008*std::pow(eps, 0.16667)+0.40244*std::pow(eps, 0.75)+eps));
102 }
103