1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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4 | // * * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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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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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_NucleonEqRhs.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_NucleonEqRhs.hh" |
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40 | #include "G4VNuclearDensity.hh" |
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41 | |
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42 | |
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43 | G4KM_NucleonEqRhs::G4KM_NucleonEqRhs(G4KM_DummyField *field, |
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44 | G4V3DNucleus * nucleus) : |
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45 | G4Mag_EqRhs(field), theNucleus(nucleus) |
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46 | { |
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47 | theMass = 0.; |
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48 | A = theNucleus->GetMassNumber(); |
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49 | factor = hbarc*hbarc*std::pow(3.*pi2*A,2./3.)/3.; |
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50 | } |
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51 | |
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52 | |
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53 | void G4KM_NucleonEqRhs::EvaluateRhsGivenB(const G4double y[], |
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54 | const G4double *, |
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55 | G4double dydx[]) const |
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56 | { |
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57 | G4double yMod = std::sqrt(y[0]*y[0]+y[1]*y[1]+y[2]*y[2]); |
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58 | G4double e = std::sqrt(theMass*theMass+y[3]*y[3]+y[4]*y[4]+y[5]*y[5]); |
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59 | |
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60 | // y[0..2] is position |
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61 | // y[3..5] is momentum (and not mom.direction) |
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62 | |
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63 | dydx[0] = c_light*y[3]/e; // |
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64 | dydx[1] = c_light*y[4]/e; // dq/dt=dH/dp = c*p/e |
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65 | dydx[2] = c_light*y[5]/e; // |
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66 | |
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67 | /* |
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68 | * // debug |
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69 | * G4cout << " Nucleon RHS : 0..2(dpos/dt) " << |
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70 | * dydx[0] << " " << |
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71 | * dydx[1] << " " << |
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72 | * dydx[2] << " " << G4endl; |
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73 | */ |
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74 | |
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75 | |
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76 | // V=K*rho(r) ==> dydx[3] = -dV/dr*dr/dx = -K*d(rho)/dr*dr/dx. |
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77 | // GF should be V=K*rho(r) ==> dydx[3] = -dV/dr*dr/dx = -K*d(rho)/dr*dr/dt |
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78 | // GF and dV/dt = dE/dt ==> dp/dt = dE/dt * dp/dE = dE/dt *e/p |
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79 | // Idem for dydx[4] and dydx[5] |
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80 | |
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81 | G4ThreeVector pos(y[0],y[1],y[2]); |
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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 | // do not check for theMass != 0 : it is an error and core dump will signal it |
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86 | |
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87 | G4double density= nuclearDensity->GetDensity(pos); |
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88 | G4double deriv(0); |
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89 | if (density > 0 ) deriv = (factor/theMass)* |
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90 | std::pow(density, -1./3.)*nuclearDensity->GetDeriv(pos); |
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91 | |
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92 | // dydx[3] = yMod == 0 ? 0 : -deriv*y[0]/yMod; |
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93 | // dydx[4] = yMod == 0 ? 0 : -deriv*y[1]/yMod; |
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94 | // dydx[5] = yMod == 0 ? 0 : -deriv*y[2]/yMod; |
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95 | dydx[3] = yMod == 0 ? 0 : deriv*y[0]/yMod*c_light; |
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96 | dydx[4] = yMod == 0 ? 0 : deriv*y[1]/yMod*c_light; |
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97 | dydx[5] = yMod == 0 ? 0 : deriv*y[2]/yMod*c_light; |
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98 | |
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99 | |
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100 | /* |
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101 | * // debug |
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102 | * G4cout << " Nucleon RHS : 3..5(dE/dt) " << |
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103 | * dydx[3] << " " << |
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104 | * dydx[4] << " " << |
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105 | * dydx[5] << " " << G4endl; |
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106 | */ |
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107 | } |
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108 | |
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109 | |
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110 | |
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111 | |
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