Gabriele Cosmo
123 lines
4.5 KiB
C++
123 lines
4.5 KiB
C++
//
|
|
// ********************************************************************
|
|
// * License and Disclaimer *
|
|
// * *
|
|
// * The Geant4 software is copyright of the Copyright Holders of *
|
|
// * the Geant4 Collaboration. It is provided under the terms and *
|
|
// * conditions of the Geant4 Software License, included in the file *
|
|
// * LICENSE and available at http://cern.ch/geant4/license . These *
|
|
// * include a list of copyright holders. *
|
|
// * *
|
|
// * Neither the authors of this software system, nor their employing *
|
|
// * institutes,nor the agencies providing financial support for this *
|
|
// * work make any representation or warranty, express or implied, *
|
|
// * regarding this software system or assume any liability for its *
|
|
// * use. Please see the license in the file LICENSE and URL above *
|
|
// * for the full disclaimer and the limitation of liability. *
|
|
// * *
|
|
// * This code implementation is the result of the scientific and *
|
|
// * technical work of the GEANT4 collaboration. *
|
|
// * By using, copying, modifying or distributing the software (or *
|
|
// * any work based on the software) you agree to acknowledge its *
|
|
// * use in resulting scientific publications, and indicate your *
|
|
// * acceptance of all terms of the Geant4 Software license. *
|
|
// ********************************************************************
|
|
//
|
|
// G4RToEConvForPositron class implementation
|
|
//
|
|
// Author: H.Kurashige, 05 October 2002 - First implementation
|
|
// --------------------------------------------------------------------
|
|
|
|
#include "G4RToEConvForPositron.hh"
|
|
#include "G4ParticleDefinition.hh"
|
|
#include "G4ParticleTable.hh"
|
|
#include "G4Material.hh"
|
|
#include "G4PhysicsLogVector.hh"
|
|
|
|
#include "G4ios.hh"
|
|
#include "G4PhysicalConstants.hh"
|
|
#include "G4SystemOfUnits.hh"
|
|
|
|
// --------------------------------------------------------------------
|
|
G4RToEConvForPositron::G4RToEConvForPositron()
|
|
: G4VRangeToEnergyConverter()
|
|
{
|
|
theParticle = G4ParticleTable::GetParticleTable()->FindParticle("e+");
|
|
if (theParticle == nullptr)
|
|
{
|
|
#ifdef G4VERBOSE
|
|
if (GetVerboseLevel()>0)
|
|
{
|
|
G4cout << "G4RToEConvForPositron::G4RToEConvForPositron() - ";
|
|
G4cout << "Positron is not defined !!" << G4endl;
|
|
}
|
|
#endif
|
|
}
|
|
else
|
|
{
|
|
Mass = theParticle->GetPDGMass();
|
|
}
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
G4RToEConvForPositron::~G4RToEConvForPositron()
|
|
{
|
|
}
|
|
|
|
// **********************************************************************
|
|
// ************************* ComputeLoss ********************************
|
|
// **********************************************************************
|
|
G4double G4RToEConvForPositron::ComputeLoss(G4double AtomicNumber,
|
|
G4double KineticEnergy)
|
|
{
|
|
const G4double cbr1=0.02, cbr2=-5.7e-5, cbr3=1., cbr4=0.072;
|
|
const G4double Tlow=10.*keV, Thigh=1.*GeV;
|
|
|
|
// calculate dE/dx for electrons
|
|
if( std::fabs(AtomicNumber-Z)>0.1 )
|
|
{
|
|
Z = AtomicNumber;
|
|
taul = Tlow/Mass;
|
|
ionpot = 1.6e-5*MeV*std::exp(0.9*std::log(Z))/Mass;
|
|
ionpotlog = std::log(ionpot);
|
|
}
|
|
|
|
G4double tau = KineticEnergy/Mass;
|
|
G4double dEdx;
|
|
|
|
if(tau<taul)
|
|
{
|
|
G4double t1 = taul+1.;
|
|
G4double t2 = taul+2.;
|
|
G4double tsq = taul*taul;
|
|
G4double beta2 = taul*t2/(t1*t1);
|
|
G4double f = 2.*std::log(taul)
|
|
-(6.*taul+1.5*tsq-taul*(1.-tsq/3.)/t2
|
|
-tsq*(0.5-tsq/12.)/(t2*t2))/(t1*t1);
|
|
dEdx = (std::log(2.*taul+4.)-2.*ionpotlog+f)/beta2;
|
|
dEdx = twopi_mc2_rcl2*Z*dEdx;
|
|
G4double clow = dEdx*std::sqrt(taul);
|
|
dEdx = clow/std::sqrt(KineticEnergy/Mass);
|
|
}
|
|
else
|
|
{
|
|
G4double t1 = tau+1.;
|
|
G4double t2 = tau+2.;
|
|
G4double tsq = tau*tau;
|
|
G4double beta2 = tau*t2/(t1*t1);
|
|
G4double f = 2.*std::log(tau)
|
|
- (6.*tau+1.5*tsq-tau*(1.-tsq/3.)/t2
|
|
-tsq*(0.5-tsq/12.)/(t2*t2))/(t1*t1);
|
|
dEdx = (std::log(2.*tau+4.)-2.*ionpotlog+f)/beta2;
|
|
dEdx = twopi_mc2_rcl2*Z*dEdx;
|
|
|
|
// loss from bremsstrahlung follows
|
|
G4double cbrem = (cbr1+cbr2*Z)
|
|
* (cbr3+cbr4*std::log(KineticEnergy/Thigh));
|
|
cbrem = Z*(Z+1.)*cbrem*tau/beta2;
|
|
cbrem *= bremfactor;
|
|
dEdx += twopi_mc2_rcl2*cbrem;
|
|
}
|
|
return dEdx;
|
|
}
|