Geant4  9.6.p02
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Macros Groups Pages
G4KM_OpticalEqRhs.cc
Go to the documentation of this file.
1 //
2 // ********************************************************************
3 // * License and Disclaimer *
4 // * *
5 // * The Geant4 software is copyright of the Copyright Holders of *
6 // * the Geant4 Collaboration. It is provided under the terms and *
7 // * conditions of the Geant4 Software License, included in the file *
8 // * LICENSE and available at http://cern.ch/geant4/license . These *
9 // * include a list of copyright holders. *
10 // * *
11 // * Neither the authors of this software system, nor their employing *
12 // * institutes,nor the agencies providing financial support for this *
13 // * work make any representation or warranty, express or implied, *
14 // * regarding this software system or assume any liability for its *
15 // * use. Please see the license in the file LICENSE and URL above *
16 // * for the full disclaimer and the limitation of liability. *
17 // * *
18 // * This code implementation is the result of the scientific and *
19 // * technical work of the GEANT4 collaboration. *
20 // * By using, copying, modifying or distributing the software (or *
21 // * any work based on the software) you agree to acknowledge its *
22 // * use in resulting scientific publications, and indicate your *
23 // * acceptance of all terms of the Geant4 Software license. *
24 // ********************************************************************
25 //
26 //
27 // -------------------------------------------------------------------
28 // GEANT 4 class implementation file
29 //
30 // CERN, Geneva, Switzerland
31 //
32 // File name: G4KM_OpticalEqRhs.cc
33 //
34 // Author: Alessandro Brunengo (Alessandro.Brunengo@ge.infn.it)
35 //
36 // Creation date: 5 June 2000
37 // -------------------------------------------------------------------
38 
39 #include "G4KM_OpticalEqRhs.hh"
40 #include "G4PhysicalConstants.hh"
41 #include "G4NucleiProperties.hh"
42 #include "G4VNuclearDensity.hh"
43 #include "G4HadTmpUtil.hh"
44 
46  G4V3DNucleus * nucleus) :
47  G4Mag_EqRhs(field), theNucleus(nucleus)
48 {
49  theFactor = 0;
50  theMass = 0;
51 }
52 
53 
54 void G4KM_OpticalEqRhs::SetFactor(G4double mass, G4double opticalParameter)
55 {
56  G4double A = theNucleus->GetMassNumber();
57  G4double Z = theNucleus->GetCharge();
59  G4double nucleusMass = Z*proton_mass_c2+(A-Z)*neutron_mass_c2+bindingEnergy;
60  G4double reducedMass = mass*nucleusMass/(mass+nucleusMass);
61 
62  G4double nucleonMass = (proton_mass_c2+neutron_mass_c2)/2;
63 
64 // _factor in (MeV*fermi)*fermi/MeV = fermi*fermi -- need to have A as density normalized to 1
65  theFactor = 2*pi*hbarc*hbarc*(1+mass/nucleonMass)* opticalParameter/reducedMass * A;
66 
67  theMass = mass;
68 }
69 
70 
72  G4double dydx[]) const
73 {
74  G4double yMod = std::sqrt(y[0]*y[0]+y[1]*y[1]+y[2]*y[2]);
75  G4double e = std::sqrt(theMass*theMass+y[3]*y[3]+y[4]*y[4]+y[5]*y[5]);
76  dydx[0] = c_light*y[3]/e; //
77  dydx[1] = c_light*y[4]/e; // dq/dt=dH/dp = c*p/e
78  dydx[2] = c_light*y[5]/e; //
79 
80 // V=K*rho(r) ==> dydx[3] = -dV/dr*dr/dx = -K*d(rho)/dr*dr/dx.
81 // Idem for dydx[4] and dydx[5]
82 
83  const G4VNuclearDensity * nuclearDensity=theNucleus->GetNuclearDensity();
84 
85  G4ThreeVector pos(y[0],y[1],y[2]);
86  G4double deriv = theFactor*nuclearDensity->GetDeriv(pos);
87 
88  dydx[3] = yMod == 0 ? 0 : -deriv*y[0]/yMod*c_light;
89  dydx[4] = yMod == 0 ? 0 : -deriv*y[1]/yMod*c_light;
90  dydx[5] = yMod == 0 ? 0 : -deriv*y[2]/yMod*c_light;
91 }
92 
93 
94 
95