Gabriele Cosmo
115 lines
4.2 KiB
C++
115 lines
4.2 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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//
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// -------------------------------------------------------------------
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// GEANT 4 class implementation file
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//
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// CERN, Geneva, Switzerland
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//
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// File name: G4KM_NucleonEqRhs.cc
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//
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// Author: Alessandro Brunengo (Alessandro.Brunengo@ge.infn.it)
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//
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// Creation date: 5 June 2000
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// -------------------------------------------------------------------
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#include "G4KM_NucleonEqRhs.hh"
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#include "G4VNuclearDensity.hh"
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#include "G4PhysicalConstants.hh"
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#include "G4Pow.hh"
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G4KM_NucleonEqRhs::G4KM_NucleonEqRhs(G4KM_DummyField *field,
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G4V3DNucleus * nucleus) :
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G4Mag_EqRhs(field), theNucleus(nucleus)
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{
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theMass = 0.;
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A = theNucleus->GetMassNumber();
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factor = hbarc*hbarc*G4Pow::GetInstance()->A23(3.*pi2*A)/3.;
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}
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void G4KM_NucleonEqRhs::EvaluateRhsGivenB(const G4double y[],
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const G4double *,
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G4double dydx[]) const
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{
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G4double yMod = std::sqrt(y[0]*y[0]+y[1]*y[1]+y[2]*y[2]);
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G4double e = std::sqrt(theMass*theMass+y[3]*y[3]+y[4]*y[4]+y[5]*y[5]);
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// y[0..2] is position
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// y[3..5] is momentum (and not mom.direction)
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dydx[0] = c_light*y[3]/e; //
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dydx[1] = c_light*y[4]/e; // dq/dt=dH/dp = c*p/e
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dydx[2] = c_light*y[5]/e; //
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/*
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* // debug
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* G4cout << " Nucleon RHS : 0..2(dpos/dt) " <<
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* dydx[0] << " " <<
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* dydx[1] << " " <<
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* dydx[2] << " " << G4endl;
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*/
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// V=K*rho(r) ==> dydx[3] = -dV/dr*dr/dx = -K*d(rho)/dr*dr/dx.
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// GF should be V=K*rho(r) ==> dydx[3] = -dV/dr*dr/dx = -K*d(rho)/dr*dr/dt
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// GF and dV/dt = dE/dt ==> dp/dt = dE/dt * dp/dE = dE/dt *e/p
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// Idem for dydx[4] and dydx[5]
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G4ThreeVector pos(y[0],y[1],y[2]);
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const G4VNuclearDensity * nuclearDensity=theNucleus->GetNuclearDensity();
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// do not check for theMass != 0 : it is an error and core dump will signal it
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G4double density= nuclearDensity->GetDensity(pos);
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G4double deriv(0);
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if (density > 0 ) deriv = (factor/theMass)/
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G4Pow::GetInstance()->A13(density)*nuclearDensity->GetDeriv(pos);
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// dydx[3] = yMod == 0 ? 0 : -deriv*y[0]/yMod;
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// dydx[4] = yMod == 0 ? 0 : -deriv*y[1]/yMod;
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// dydx[5] = yMod == 0 ? 0 : -deriv*y[2]/yMod;
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dydx[3] = yMod == 0 ? 0 : deriv*y[0]/yMod*c_light;
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dydx[4] = yMod == 0 ? 0 : deriv*y[1]/yMod*c_light;
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dydx[5] = yMod == 0 ? 0 : deriv*y[2]/yMod*c_light;
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/*
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* // debug
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* G4cout << " Nucleon RHS : 3..5(dE/dt) " <<
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* dydx[3] << " " <<
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* dydx[4] << " " <<
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* dydx[5] << " " << G4endl;
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*/
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}
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// Here by design, but it is unnecessary for nuclear fields
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void G4KM_NucleonEqRhs::SetChargeMomentumMass(G4ChargeState,G4double ,G4double )
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{
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}
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