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1 //
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25 //
26 //
27 // -------------------------------------------------------------------
28 //
29 // GEANT4 Class file
30 //
31 //
32 // File name: G4VhElectronicStoppingPower
33 //
34 // Author: V.Ivanchenko (Vladimir.Ivanchenko@cern.ch)
35 //
36 // Creation date: 20 July 2000
37 //
38 // Modifications:
39 // 20/07/2000 V.Ivanchenko First implementation
40 //
41 // Class Description:
42 //
43 // Low energy hadrons/ions electronic stopping power parametrisation
44 //
45 // Class Description: End
46 //
47 // -------------------------------------------------------------------
48 //
49 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
50
51 #include "G4VhElectronicStoppingPower.hh"
52 #include "G4SystemOfUnits.hh"
53 #include "G4UnitsTable.hh"
54 #include "G4Exp.hh"
55
56 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
57
58 G4VhElectronicStoppingPower::G4VhElectronicStoppingPower():
59 theHeMassAMU(4.0026)
60 {;}
61
62 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
63
64 G4VhElectronicStoppingPower::~G4VhElectronicStoppingPower()
65 {;}
66
67 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
68
69 G4double G4VhElectronicStoppingPower::HeEffChargeSquare(
70 const G4double z,
71 const G4double kineticEnergyHe) const
72 {
73 // The aproximation of He effective charge from:
74 // J.F.Ziegler, J.P. Biersack, U. Littmark
75 // The Stopping and Range of Ions in Matter,
76 // Vol.1, Pergamon Press, 1985
77
78 static const G4double c[6] = {0.2865, 0.1266, -0.001429,
79 0.02402,-0.01135, 0.001475} ;
80
81 G4double e = std::log( std::max( 1.0, kineticEnergyHe/(keV*GetHeMassAMU()))) ;
82 G4double x = c[0] ;
83 G4double y = 1.0 ;
84 for (G4int i=1; i<6; i++) {
85 y *= e ;
86 x += y * c[i] ;
87 }
88
89 G4double w = 7.6 - e ;
90 w = 1.0 + (0.007 + 0.00005*z) * G4Exp( -w*w ) ;
91 w = 4.0 * (1.0 - G4Exp(-x)) * w * w ;
92 return w;
93 }
94