G4MicroElecLOPhononModel.cc

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//
// G4MicroElecLOPhononModel.cc, 
//               2020/05/20 P. Caron, C. Inguimbert are with ONERA [b] 
//                          Q. Gibaru is with CEA [a], ONERA [b] and CNES [c]
//                          M. Raine and D. Lambert are with CEA [a]
//
// A part of this work has been funded by the French space agency(CNES[c])
// [a] CEA, DAM, DIF - 91297 ARPAJON, France
// [b] ONERA - DPHY, 2 avenue E.Belin, 31055 Toulouse, France
// [c] CNES, 18 av.E.Belin, 31401 Toulouse CEDEX, France
//
// Based on the following publications
//
// - J. Pierron, C. Inguimbert, M. Belhaj, T. Gineste, J. Puech, M. Raine
//   Electron emission yield for low energy electrons: 
//   Monte Carlo simulation and experimental comparison for Al, Ag, and Si
//   Journal of Applied Physics 121 (2017) 215107. 
//   https://doi.org/10.1063/1.4984761
//
// - P. Caron,
//   Study of Electron-Induced Single-Event Upset in Integrated Memory Devices
//   PHD, 16th October 2019
//
// - Q.Gibaru, C.Inguimbert, P.Caron, M.Raine, D.Lambert, J.Puech, 
//   Geant4 physics processes for microdosimetry and secondary electron emission simulation : 
//   Extension of MicroElec to very low energies and new materials
//   NIM B, 2020, in review.
//
////////////////////////////////////////////////////////////////////////
 
#include "G4MicroElecLOPhononModel.hh"
#include "G4SystemOfUnits.hh"
#include "G4PhysicalConstants.hh"
 
G4MicroElecLOPhononModel::G4MicroElecLOPhononModel(const G4ParticleDefinition*,
                                                   const G4String& nam) 
  : G4VEmModel(nam),isInitialised(false)
{
  G4cout << "Phonon model is constructed " << G4endl
         << "Phonon Energy = " << phononEnergy / eV << " eV  "<< G4endl;
}
 
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void G4MicroElecLOPhononModel::Initialise(const G4ParticleDefinition*,
                          const G4DataVector& /*cuts*/)
{
  fParticleChangeForGamma = GetParticleChangeForGamma();
  isInitialised = true;
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
G4double G4MicroElecLOPhononModel::
CrossSectionPerVolume(const G4Material* material,
                      const G4ParticleDefinition* p,
                            G4double ekin,
                            G4double, G4double)
{
  const G4double e = CLHEP::eplus / CLHEP::coulomb;
  const G4double m0 = CLHEP::electron_mass_c2 / (CLHEP::c_squared*CLHEP::kg);
  const G4double h = CLHEP::hbar_Planck * CLHEP::s/ (CLHEP::m2*CLHEP::kg);
  const G4double eps0 = CLHEP::epsilon0 * CLHEP::m/ (CLHEP::farad);
  const G4double kb = CLHEP::k_Boltzmann * CLHEP::kelvin/ CLHEP::joule;
  const G4double T = 300;
  G4double eps = 9;
  G4double einf = 3;
 
  const G4DataVector cuts;
  Initialise(p, cuts);
 
  if (material->GetName() != "G4_SILICON_DIOXIDE"
   && material->GetName() != "G4_ALUMINUM_OXIDE"
   && material->GetName() != "G4_BORON_NITRIDE")
  {
    return 1 / DBL_MAX;
  }
 
  G4double E =(ekin/eV)*e;
 
  if (material->GetName() == "G4_ALUMINUM_OXIDE")
  {
    eps = 9;
    einf = 3;
    phononEnergy = 0.1*eV;
  }
  if (material->GetName() == "G4_SILICON_DIOXIDE")
  {
    eps = 3.84;
    einf = 2.25;    
    phononEnergy = (0.75*0.153+0.25*0.063 )* eV;
  }
 
  // Nuclear Instruments and Methods in Physics Research Section B:
  // Beam Interactions with Materials and Atoms
  // Volume 454, 1 September 2019, Pages 14 - 22
  // Nuclear Instruments and Methods in Physics Research Section B:
  // Beam Interactions with Materials and Atoms
  // Monte Carlo modeling of low - energy electron - induced secondary
  // electron emission yields in micro - architected boron nitride surfaces
 
  if (material->GetName() == "G4_BORON_NITRIDE")
  {
    eps = 7.1;
    einf = 4.5;
    phononEnergy = 0.17 * eV;
  }
 
  G4double hw = (phononEnergy / eV) * e;
  G4double n = 1.0 / (std::exp(hw / (kb*T)) - 1); //Phonon distribution
  
  if (E<=hw)
  {
    return 1 / DBL_MAX;
  }
 
  if (absor)  // Absorption
  {
    Eprim = E + hw;
    signe = -1;
  }
  else        // Emission
  {
    Eprim = E - hw;
    signe = +1;
  }
 
  G4double racine = std::sqrt(1 + ((-signe*hw) / E));
  G4double P = (std::pow(e, 2) / (4 * pi*eps0*h*h)) * (n + 0.5 + signe*0.5) * ((1 / einf) - (1 / eps)) * std::sqrt(m0 / (2 * E)) *hw* std::log((1 + racine) / (signe * 1 + ((-signe)*racine)));
  G4double MFP = (std::sqrt(2 * E / m0) / P)*m;
 
  if (material->GetName() == "G4_SILICON_DIOXIDE") { return 2 / MFP; }
  return 1/(MFP);                   
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
void G4MicroElecLOPhononModel::
SampleSecondaries(std::vector<G4DynamicParticle*>*,
                  const G4MaterialCutsCouple*,
                  const G4DynamicParticle* aDynamicElectron,
                  G4double, G4double)
{
  G4double E = aDynamicElectron->GetKineticEnergy();
  Eprim = (absor) ? E + phononEnergy : E - phononEnergy;   
 
  G4double rand = G4UniformRand();
  G4double B = (E + Eprim + 2 * std::sqrt(E*Eprim))
             / (E + Eprim - 2 * std::sqrt(E*Eprim));
  G4double cosTheta = ((E + Eprim) / (2 * std::sqrt(E*Eprim)))
                    * (1 - std::pow(B, rand)) + std::pow(B, rand);
  if(Interband)
  {
    cosTheta = 1 - 2 * G4UniformRand(); //Isotrope
  }
  G4double phi = twopi * G4UniformRand();
  G4ThreeVector zVers = aDynamicElectron->GetMomentumDirection();
  G4ThreeVector xVers = zVers.orthogonal();
  G4ThreeVector yVers = zVers.cross(xVers);
  
  G4double xDir = std::sqrt(1. - cosTheta*cosTheta);
  G4double yDir = xDir;
  xDir *= std::cos(phi);
  yDir *= std::sin(phi);
  
  G4ThreeVector zPrimeVers((xDir*xVers + yDir*yVers + cosTheta*zVers));
  
  fParticleChangeForGamma->ProposeMomentumDirection(zPrimeVers.unit());
  fParticleChangeForGamma->SetProposedKineticEnergy(Eprim);
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......