1. Centre de Toulouse Radiation interaction with matter 1

2. Centre de Toulouse / DESP Outline Introduction Generalities cross section dE/dx LET and NIEL Proton electrons range, practical range Ionising and non ionising dose Conclusion 2

3. Centre de Toulouse / DESP Particles of interest h Photons x,  protons [1MeV, 1GeV] electrons [10keV, 10 MeV] ions [1 MeV/uma, 1 GeV/uma] 3

4. Centre de Toulouse / DESP GENERAL : Energy loss by unit path length 4 dx Interaction dE E - dE E dE dx Assuming a straight line trajectory

5. Centre de Toulouse / DESP Nature of the medium Si e- Si e- Si e- Si e- Si e- Si e- Si e- Si e- Si e- Si e- Si e- silicium Incident particle Coulombic Scattering v v v Incident particle Nuclear Reaction Slowing down 5,4 A 0,9 A a)b) Slowing down Electrons act as a viscous medium that slow down incident particle In addition, the probability to encounter a nuclei is not nul 7

6. Centre de Toulouse / DESP Ionisation and Displacement for charged particles interaction with electrons - ionisation - Coulombic inelastic scattering interaction with nuclei - displacements - elastic scattering - nuclear reaction vacancy interstitial 8

7. Centre de Toulouse / DESP Total stopping power 9 Not negligeable for energetic electron in heavy material Not negligeable for low energy protons e-nucleus Bremsstrahlung NIEL + phonon Ionising stopping power

8. Centre de Toulouse / DESP slowing down of particles Proton stopping power Unit : MeV/  m or MeV/mg.cm 2 12 dE/dx is proportional to density dE/dx is maximal when incident & target particle are identical 

9. Centre de Toulouse / DESP slowing down of particles Stopping power of electrons dE/dx is proportional to specific gravity dE/dx is maximal when incident & target particle are identical  13

10. Centre de Toulouse / DESP 14 Displacement damages P interstitial vacancy

11. Centre de Toulouse / DESP Protons E 1 eV 0,1 MeV 1 MeV 188 eV 10 MeV No more displacement Recoil energy < 25 eV Elastic scattering - Coulombic scattering - nuclear scattering Nuclear reaction 21 In silicon P Slowing down by ionisation displacement P

12. Centre de Toulouse / DESP Interaction of Charged particles with matter : electrons  - rays emission Bremsstrahlung E 1 MeV 250 keV No more displacement Recoil energy < 25 eV - Coulombic scattering Gamma Some displacements 22 Slowing down by ionisation In silicon

13. Centre de Toulouse / DESP Bremsstrahlung : Interaction of electromagnetic radiation with matter  - rays E 10 -3 eV m 1 eV 3 eV 100 eV 1 MeV 1 mm 750 nm 400 nm 10 nm 1 pm 23 Gamma ray emission by interaction with electric field of the atom of the target Z incident Z target M incident I  2 negligeable large M incident Proton Electron Heavy material with large Z target

14. Centre de Toulouse / DESP Range of particles The range is deduced from the stopping power 24 range depth Al 1 MeV electron beam Al 27 13 Material surface Range > depth Mean penetration depth

15. Centre de Toulouse / DESP Range of protons & ions 25 Ions in silicon Protons in different materials

16. Centre de Toulouse / DESP Range of electrons 26

17. Centre de Toulouse / DESP Order of magnitude 27

18. Centre de Toulouse / DESP trajectories 28 AluminiumProton (100 MeV)Aluminium Electrons (1 MeV) Back-scattered electron 10 MeV electrons in Al Bremsstrahlung 100 MeV protons in Al 84 MeV Carbon in Silicon 1 MeV electrons in Al

19. Centre de Toulouse / DESP Ionising and non ionising dose 29 Dose is the averaged energy deposited by unit of mass : J/ kg = Gray 1 Gray = 100 rad Flux  dx Deposited energy  E Surface S  atoms/cm 3 dn  scattered particles Volume Mass Incident Number of particle . NIEL

20. Centre de Toulouse / DESP Ionising Dose : Normaly incident protons 30 Due to straggling and scattering Compromise between the increase of the LET and the decrease of the flux due to scattering

21. Centre de Toulouse / DESP Al 27 13 Material surface 31 Ionising Dose : Normaly incident electrons Peack smoother than for protons as electrons are largely scattered

22. Centre de Toulouse / DESP 32 Ionising Dose : Normaly incident electrons + Bremsstrahlung Bragg Peak Dose enhancement gamma

23. Centre de Toulouse / DESP Mission ionising dose : LEO, GEO 33

24. Centre de Toulouse / DESP 34 Mission ionising dose : GPS

25. Centre de Toulouse / DESP Conclusion 37 Electron act as a viscous medium that slow down incident charged particles Interaction with electron produce ionisation (LET) Interaction with nuclei produce displacement (NIEL) Ionising and non ionising dose (Energy deposited by unit of mass)

26. Centre de Toulouse / DESP Conclusion 38 LET is used to quantify SEE effects (  SEU (LET)) NIEL is used to quantify degradation of optoelectronic components Dose is used to quantify degradation of electronic devices ( MOS, Bipolar) LET, NIEL and dose are the fondemental parameters used to quantify many degradations induced by space radiations