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G4ProtonInelasticCrossSection.cc
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25 //
26 // By JPW, working, but to be cleaned up. @@@
27 // G.Folger, 29-sept-2006: extend to 1TeV, using a constant above 20GeV
28 // 22 Dec 2006 - DHW added isotope dependence
29 // G.Folger, 25-Nov-2009: extend to 100TeV, using a constant above 20GeV
30 // V.Ivanchenko, 18-Aug-2011: migration to new design and cleanup;
31 // make it applicable for Z>1
32 //
33 
35 #include "G4SystemOfUnits.hh"
36 #include "G4DynamicParticle.hh"
37 #include "G4Proton.hh"
38 #include "G4HadTmpUtil.hh"
39 #include "G4NistManager.hh"
40 
42  : G4VCrossSectionDataSet("Axen-Wellisch"),thEnergy(19.8*CLHEP::GeV)
43 {
46 }
47 
49 {}
50 
51 G4bool
53  const G4DynamicParticle* aPart,
54  G4int Z, const G4Material*)
55 {
56  return ((1 < Z) && (aPart->GetDefinition() == theProton));
57 }
58 
60  const G4DynamicParticle* aPart,
61  G4int Z, const G4Material*)
62 {
63  return GetProtonCrossSection(aPart->GetKineticEnergy(), Z);
64 }
65 
67  G4double kineticEnergy, G4int Z)
68 {
69  if(kineticEnergy <= 0.0) { return 0.0; }
70 
71  // constant cross section above ~20GeV
72  if (kineticEnergy > thEnergy) { kineticEnergy = thEnergy; }
73 
75  G4double a13 = G4Pow::GetInstance()->powA(a,-0.3333333333);
76  G4int nOfNeutrons = G4lrint(a) - Z;
77  kineticEnergy /=GeV;
78  G4double alog10E = std::log10(kineticEnergy);
79 
80  static const G4double nuleonRadius=1.36e-15;
81  static const G4double fac=CLHEP::pi*nuleonRadius*nuleonRadius;
82 
83  G4double b0 = 2.247-0.915*(1 - a13);
84  G4double fac1 = b0*(1 - a13);
85  G4double fac2 = 1.;
86  if(nOfNeutrons > 1) { fac2=G4Log((G4double(nOfNeutrons))); }
87  G4double crossSection = 1.0E31*fac*fac2*(1. + 1./a13 - fac1);
88 
89  // high energy correction
90  crossSection *= (1 - 0.15*G4Exp(-kineticEnergy))/(1.0 - 0.0007*a);
91 
92  // first try on low energies: rise
93  G4double ff1= 0.70-0.002*a; // slope of the drop at medium energies.
94  G4double ff2= 1.00+1/a; // start of the slope.
95  G4double ff3= 0.8+18/a-0.002*a; // stephight
96 
97  G4double ff4= 1.0 - (1.0/(1+G4Exp(-8*ff1*(alog10E + 1.37*ff2))));
98 
99  crossSection *= (1 + ff3*ff4);
100 
101  // low energy return to zero
102 
103  ff1=1. - 1./a - 0.001*a; // slope of the rise
104  ff2=1.17 - 2.7/a - 0.0014*a; // start of the rise
105 
106  ff4=-8.*ff1*(alog10E + 2.0*ff2);
107 
108  crossSection *= millibarn/(1. + G4Exp(ff4));
109  return crossSection;
110 }