1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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4 | // * * |
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5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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7 | // * conditions of the Geant4 Software License, included in the file * |
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8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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9 | // * include a list of copyright holders. * |
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10 | // * * |
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11 | // * Neither the authors of this software system, nor their employing * |
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12 | // * institutes,nor the agencies providing financial support for this * |
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13 | // * work make any representation or warranty, express or implied, * |
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14 | // * regarding this software system or assume any liability for its * |
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15 | // * use. Please see the license in the file LICENSE and URL above * |
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17 | // * * |
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18 | // * This code implementation is the result of the scientific and * |
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19 | // * technical work of the GEANT4 collaboration. * |
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20 | // * By using, copying, modifying or distributing the software (or * |
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21 | // * any work based on the software) you agree to acknowledge its * |
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23 | // * acceptance of all terms of the Geant4 Software license. * |
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24 | // ******************************************************************** |
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25 | // |
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26 | // |
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27 | // ------------------------------------------------------------------- |
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28 | // GEANT 4 class implementation file |
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29 | // |
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30 | // CERN, Geneva, Switzerland |
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31 | // |
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32 | // File name: G4KM_OpticalEqRhs.cc |
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33 | // |
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34 | // Author: Alessandro Brunengo (Alessandro.Brunengo@ge.infn.it) |
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35 | // |
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36 | // Creation date: 5 June 2000 |
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37 | // ------------------------------------------------------------------- |
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38 | |
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39 | #include "G4KM_OpticalEqRhs.hh" |
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40 | #include "G4NucleiPropertiesTable.hh" |
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41 | #include "G4VNuclearDensity.hh" |
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42 | #include "G4HadTmpUtil.hh" |
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43 | |
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44 | |
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45 | G4KM_OpticalEqRhs::G4KM_OpticalEqRhs(G4KM_DummyField *field, |
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46 | G4V3DNucleus * nucleus) : |
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47 | G4Mag_EqRhs(field), theNucleus(nucleus) |
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48 | { |
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49 | theFactor = 0; |
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50 | theMass = 0; |
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51 | } |
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52 | |
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53 | |
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54 | void G4KM_OpticalEqRhs::SetFactor(G4double mass, G4double opticalParameter) |
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55 | { |
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56 | G4double A = theNucleus->GetMassNumber(); |
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57 | G4double Z = theNucleus->GetCharge(); |
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58 | G4double bindingEnergy = G4NucleiPropertiesTable::GetBindingEnergy(G4lrint(Z), G4lrint(A)); |
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59 | G4double nucleusMass = Z*proton_mass_c2+(A-Z)*neutron_mass_c2+bindingEnergy; |
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60 | G4double reducedMass = mass*nucleusMass/(mass+nucleusMass); |
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61 | |
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62 | G4double nucleonMass = (proton_mass_c2+neutron_mass_c2)/2; |
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63 | |
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64 | // _factor in (MeV*fermi)*fermi/MeV = fermi*fermi -- need to have A as density normalized to 1 |
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65 | theFactor = 2*pi*hbarc*hbarc*(1+mass/nucleonMass)* opticalParameter/reducedMass * A; |
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66 | |
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67 | theMass = mass; |
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68 | } |
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69 | |
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70 | |
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71 | void G4KM_OpticalEqRhs::EvaluateRhsGivenB(const G4double y[], const G4double *, |
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72 | G4double dydx[]) const |
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73 | { |
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74 | G4double yMod = std::sqrt(y[0]*y[0]+y[1]*y[1]+y[2]*y[2]); |
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75 | G4double e = std::sqrt(theMass*theMass+y[3]*y[3]+y[4]*y[4]+y[5]*y[5]); |
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76 | dydx[0] = c_light*y[3]/e; // |
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77 | dydx[1] = c_light*y[4]/e; // dq/dt=dH/dp = c*p/e |
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78 | dydx[2] = c_light*y[5]/e; // |
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79 | |
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80 | // V=K*rho(r) ==> dydx[3] = -dV/dr*dr/dx = -K*d(rho)/dr*dr/dx. |
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81 | // Idem for dydx[4] and dydx[5] |
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82 | |
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83 | const G4VNuclearDensity * nuclearDensity=theNucleus->GetNuclearDensity(); |
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84 | |
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85 | G4ThreeVector pos(y[0],y[1],y[2]); |
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86 | G4double deriv = theFactor*nuclearDensity->GetDeriv(pos); |
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87 | |
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88 | dydx[3] = yMod == 0 ? 0 : -deriv*y[0]/yMod*c_light; |
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89 | dydx[4] = yMod == 0 ? 0 : -deriv*y[1]/yMod*c_light; |
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90 | dydx[5] = yMod == 0 ? 0 : -deriv*y[2]/yMod*c_light; |
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91 | } |
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92 | |
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93 | |
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94 | |
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95 | |
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