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25 //
26 //
27 // G4MicroElecLOPhononModel.cc,
28 // 2020/05/20 P. Caron, C. Inguimbert are with ONERA [b]
29 // Q. Gibaru is with CEA [a], ONERA [b] and CNES [c]
30 // M. Raine and D. Lambert are with CEA [a]
31 //
32 // A part of this work has been funded by the French space agency(CNES[c])
33 // [a] CEA, DAM, DIF - 91297 ARPAJON, France
34 // [b] ONERA - DPHY, 2 avenue E.Belin, 31055 Toulouse, France
35 // [c] CNES, 18 av.E.Belin, 31401 Toulouse CEDEX, France
36 //
37 // Based on the following publications
38 //
39 // - J. Pierron, C. Inguimbert, M. Belhaj, T. Gineste, J. Puech, M. Raine
40 // Electron emission yield for low energy electrons:
41 // Monte Carlo simulation and experimental comparison for Al, Ag, and Si
42 // Journal of Applied Physics 121 (2017) 215107.
43 // https://doi.org/10.1063/1.4984761
44 //
45 // - P. Caron,
46 // Study of Electron-Induced Single-Event Upset in Integrated Memory Devices
47 // PHD, 16th October 2019
48 //
49 // - Q.Gibaru, C.Inguimbert, P.Caron, M.Raine, D.Lambert, J.Puech,
50 // Geant4 physics processes for microdosimetry and secondary electron emission simulation :
51 // Extension of MicroElec to very low energies and new materials
52 // NIM B, 2020, in review.
53 //
54 ////////////////////////////////////////////////////////////////////////
55
56 #include "G4MicroElecLOPhononModel.hh"
57 #include "G4SystemOfUnits.hh"
58 #include "G4PhysicalConstants.hh"
59
60 G4MicroElecLOPhononModel::G4MicroElecLOPhononModel(const G4ParticleDefinition*,
61 const G4String& nam)
62 : G4VEmModel(nam),isInitialised(false)
63 {
64 G4cout << "Phonon model is constructed " << G4endl
65 << "Phonon Energy = " << phononEnergy / eV << " eV "<< G4endl;
66 }
67
68 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
69
70 void G4MicroElecLOPhononModel::Initialise(const G4ParticleDefinition*,
71 const G4DataVector& /*cuts*/)
72 {
73 if (isInitialised) { return; }
74 fParticleChangeForGamma = GetParticleChangeForGamma();
75 isInitialised = true;
76 }
77
78 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
79
80 G4double G4MicroElecLOPhononModel::
81 CrossSectionPerVolume(const G4Material* material,
82 const G4ParticleDefinition* p,
83 G4double ekin,
84 G4double, G4double)
85 {
86 const G4double e = CLHEP::eplus / CLHEP::coulomb;
87 const G4double m0 = CLHEP::electron_mass_c2 / (CLHEP::c_squared*CLHEP::kg);
88 const G4double h = CLHEP::hbar_Planck * CLHEP::s/ (CLHEP::m2*CLHEP::kg);
89 const G4double eps0 = CLHEP::epsilon0 * CLHEP::m/ (CLHEP::farad);
90 const G4double kb = CLHEP::k_Boltzmann * CLHEP::kelvin/ CLHEP::joule;
91 const G4double T = 300;
92 G4double eps = 9;
93 G4double einf = 3;
94
95 const G4DataVector cuts;
96 Initialise(p, cuts);
97
98 if (material->GetName() != "G4_SILICON_DIOXIDE"
99 && material->GetName() != "G4_ALUMINUM_OXIDE"
100 && material->GetName() != "G4_BORON_NITRIDE")
101 {
102 return 1 / DBL_MAX;
103 }
104
105 G4double E =(ekin/eV)*e;
106
107 if (material->GetName() == "G4_ALUMINUM_OXIDE")
108 {
109 eps = 9;
110 einf = 3;
111 phononEnergy = 0.1*eV;
112 }
113 if (material->GetName() == "G4_SILICON_DIOXIDE")
114 {
115 eps = 3.84;
116 einf = 2.25;
117 phononEnergy = (0.75*0.153+0.25*0.063 )* eV;
118 }
119
120 // Nuclear Instruments and Methods in Physics Research Section B:
121 // Beam Interactions with Materials and Atoms
122 // Volume 454, 1 September 2019, Pages 14 - 22
123 // Nuclear Instruments and Methods in Physics Research Section B:
124 // Beam Interactions with Materials and Atoms
125 // Monte Carlo modeling of low - energy electron - induced secondary
126 // electron emission yields in micro - architected boron nitride surfaces
127
128 if (material->GetName() == "G4_BORON_NITRIDE")
129 {
130 eps = 7.1;
131 einf = 4.5;
132 phononEnergy = 0.17 * eV;
133 }
134
135 G4double hw = (phononEnergy / eV) * e;
136 G4double n = 1.0 / (std::exp(hw / (kb*T)) - 1); //Phonon distribution
137
138 if (absor) // Absorption
139 {
140 Eprim = E + hw;
141 signe = -1;
142 }
143 else // Emission
144 {
145 Eprim = E - hw;
146 signe = +1;
147 }
148
149 G4double racine = std::sqrt(1 + ((-signe*hw) / E));
150 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)));
151 G4double MFP = (std::sqrt(2 * E / m0) / P)*m;
152
153 if (material->GetName() == "G4_SILICON_DIOXIDE") { return 2 / MFP; }
154 return 1/(MFP);
155 // correction CI 12/1/2023 add
156 }
157
158 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
159
160 void G4MicroElecLOPhononModel::
161 SampleSecondaries(std::vector<G4DynamicParticle*>*,
162 const G4MaterialCutsCouple*,
163 const G4DynamicParticle* aDynamicElectron,
164 G4double, G4double)
165 {
166 G4double E = aDynamicElectron->GetKineticEnergy();
167 Eprim = (absor) ? E + phononEnergy : E - phononEnergy;
168
169 G4double rand = G4UniformRand();
170 G4double B = (E + Eprim + 2 * std::sqrt(E*Eprim))
171 / (E + Eprim - 2 * std::sqrt(E*Eprim));
172 G4double cosTheta = ((E + Eprim) / (2 * std::sqrt(E*Eprim)))
173 * (1 - std::pow(B, rand)) + std::pow(B, rand);
174 if(Interband)
175 {
176 cosTheta = 1 - 2 * G4UniformRand(); //Isotrope
177 }
178 G4double phi = twopi * G4UniformRand();
179 G4ThreeVector zVers = aDynamicElectron->GetMomentumDirection();
180 G4ThreeVector xVers = zVers.orthogonal();
181 G4ThreeVector yVers = zVers.cross(xVers);
182
183 G4double xDir = std::sqrt(1. - cosTheta*cosTheta);
184 G4double yDir = xDir;
185 xDir *= std::cos(phi);
186 yDir *= std::sin(phi);
187
188 G4ThreeVector zPrimeVers((xDir*xVers + yDir*yVers + cosTheta*zVers));
189
190 fParticleChangeForGamma->ProposeMomentumDirection(zPrimeVers.unit());
191 fParticleChangeForGamma->SetProposedKineticEnergy(Eprim);
192 }
193
194 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
195