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G4WentzelVIRelXSection.cc
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25 //
26 //
27 // -------------------------------------------------------------------
28 //
29 // GEANT4 Class file
30 //
31 //
32 // File name: G4WentzelVIRelXSection
33 //
34 // Author: V.Ivanchenko
35 //
36 // Creation date: 08.06.2012 from G4WentzelOKandVIxSection
37 //
38 // Modifications:
39 //
40 //
41 
42 // -------------------------------------------------------------------
43 //
44 
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47 
48 #include "G4WentzelVIRelXSection.hh"
49 
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52 G4WentzelVIRelXSection::G4WentzelVIRelXSection()
53 {}
54 
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56 
57 G4WentzelVIRelXSection::~G4WentzelVIRelXSection()
58 {}
59 
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61 
62 G4double G4WentzelVIRelXSection::SetupKinematic(G4double kinEnergy,
63  const G4Material* mat)
64 {
65  if(kinEnergy != tkin || mat != currentMaterial) {
66 
67  currentMaterial = mat;
68  tkin = kinEnergy;
69  G4double momLab2 = tkin*(tkin + 2.0*mass);
70 
71  G4double etot = tkin + mass;
72  G4double ptot = std::sqrt(momLab2);
73  G4double m12 = mass*mass;
74 
75  // relativistic reduced mass from publucation
76  // A.P. Martynenko, R.N. Faustov, Teoret. mat. Fiz. 64 (1985) 179
77 
78  //incident particle & target nucleus
79  G4double Ecm = std::sqrt(m12 + targetMass*targetMass + 2.0*etot*targetMass);
80  G4double mu_rel = mass*targetMass/Ecm;
81  G4double momCM = ptot*targetMass/Ecm;
82  // relative system
83  mom2 = momCM*momCM;
84  invbeta2 = 1.0 + mu_rel*mu_rel/mom2;
85 
86  factB = spin/invbeta2;
87  factD = std::sqrt(mom2)/targetMass;
88  cosTetMaxNuc = isCombined ?
89  std::max(cosThetaMax, 1.-factorA2*mat->GetIonisation()->GetInvA23()/mom2)
90  : cosThetaMax;
91  }
92  return cosTetMaxNuc;
93 }
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