1. 1 Space Radiation Effects Tutorial E. De Donder (BIRA) 23/03/2012 at ROB  www.spenvis.oma.be www.spenvis.oma.be

2. 2 Outline 1.General overview picture 2.Radiation environment  GCR particles  Solar particles  Trapped particles  Secondary particles 3.Radiation effects  Total Ionizing Dose (TID)  Displacement Damage (DDD)  Single Event Effects (SEE)  S/c charging 4.Solar storm threat-matrix

3. 3 Radiation environment Plasma environment Neutral environment Microparticle environment + drag

4. 4 Radiation environment (1/4): GCR particles  protons and heavy ions (Z>1, mostly fully ionized)  E ~ 0.01 – 10 3 GeV/n  modulated by solar cycle, Forbush decrease due to CME  anomalous component : 1x ionised He, N, O, Ne, Ar with 10 < E < 100 MeV/n → only during sol.min. Energy required to penetrate Earth’s magnetic field (Stassinopoulos et al., 2003) SPENVIS-4.5 Magnetic rigidity = momentum per charge

5. 5 Radiation environment (2/4): Solar particles Solar wind: electrons, protons, heavy ions (single ionised) ~0.5 – 2.0 keV/n → acceleration to high energies (up to 500 MeV/n and higher) - during solar flares (impulsive SEP event, heavy ion rich) - by shocks associated to CMEs (gradual SEP event, proton rich) SPENVIS -4.5

6. 6 Radiation environment (3/4): Trapped particles  Electrons : -0.04 – 7 MeV -L = ~ 1.5 (inner zone) and 2.8 < L < 12 (outer zone) → highly dynamic -solar wind, ionosphere  Protons : - 0.04 – 500 MeV -1.5 < L < 2.5 -cosmic ray albedo neutron decay  SAA: South Atlantic Anomaly / Southeast Asian Anomaly Polar horns E.J. Daly, 1996 SPENVIS – 4.5

7. 7 SPENVIS -4.5

8. 8 Radiation environment (4/4): Secondary particles → interaction with s/c shielding material Secondary particle fluence energy spectra after 20-mm aluminum shield for an incident trapped proton spectrum accumulated over one year. The spectra are from a 10 incident protons simulation.

9. 9 GCR and SEP flux satellite (GOES/ACE) data, observed during Halloween event 2003) propagated (with NAIRAS model) to top level atmosphere and cruise altitude (10-12 km). (from C. Mertens, 2010) → interaction with atmosphere

10. 10 MIT OpenCourseWare

11. 11 Radiation Effects Energy deposition → Dose in rads (M) or Gy: dE/dm Space environment dose rate ~10 -4 – 10 -2 rad/s → low Long-term effects → degradation of performance Short-term effects → soft and hard errors Ionisation Dose LET (linear energy transfer) Non-ionisation Dose NIEL (non-ionising energy loss) X fluence

12. 12 (Adams et al., 1987) Summers, 1993.

13. 13 ▪ cumulative long term ionizing damage due to the production of electron – hole pairs  effects: - build up of charges/defects → device degradation (e.g. V th shift and increasing leakage currents) (e.g. V th shift and increasing leakage currents) - DNA damage ▪ main source: > 0.1 MeV protons (trapped & solar), electrons (trapped) Radiation Effects (1/4): Total Ionizing Dose (TID)

14. 14 ▪ cumulative long term non-ionizing damage due to the production of Frenkel pairs (vacancies and interstitials)  effects: lattice defects → parametric degradation (optical devices) like P out decrease of solar cells ▪ main source: > 150 keV (0.3 – 5 MeV for solar cells) electrons (trapped) > 1 MeV (1 – 10 MeV for solar cells) protons (trapped and solar) neutrons Radiation Effects (2/4): Displacement Damage Dose (DDD)

15. 15 SOHO’s Solar Array Degradation History Solar array degradation: Net loss in two week period 1.1%

16. 16 ▪ stochastic effect caused by the production of small, spurious charge pulses within electronics ▪ processes: - direct ionization by single particle (heavy ion) - induced ionization via nucl. reaction (proton & neutron) ▪ effects: → errors in memory devices like logic change (soft) and burn-out (hard) → lit up of pixels of CCD by creation of free charge → DNA damage  main source: > 10 MeV/n protons (trapped & solar), heavy ions (GCR & solar), neutrons solar), neutrons Radiation Effects (3/4): Single Event Effect (SEE) H. Becker, et al, IEEE Trans. Nucl. Sci., 49(3082), 2002 charge ~Z 2

17. 17 SOHO image: “snowing on 14 July 2000 October 1989 event UoSAT-2 ( polar orbit of altitude about 700km)

18. 18 Radiation Effects (4/4): S/c charging ▪ accumulation of electric charge on s/c surface from natural space plasma → surface charging –Main source : 0.01 – 100 keV electrons ▪ accumulation of electric charge on internal dielectrics from penetrating high-energy electrons → internal dielectric charging –Main source: > 100 keV electrons (trapped) - “Killer electrons” ▪ effects: (breakdown) discharges

19. 19 During substorms, a hot plasma is injected from the magnetotail into the nightside high-altitude equatorial regions. The electrons gradient- curvature drift towards dawn and can dominate the charge balance on a vehicle The hazard arises when adjacent surfaces rise to different enough potentials to drive a discharge A discharge can introduce unintended signals of tens of volts amplitude in command and power lines High speed solar wind and killer electrons Surface damage in a C2 MOS Capacitor (Image from JPL)

20. 20 Summary: Radiation Effects in Space Radiation Effect Impact on Mission Space Environment Natural Variation in Environment surface charging biasing of instrument readings power drain physical damage 0.01 - 100 keV: electrons minutes surface dose changes in thermal, electrical, and optical properties UV, atomic oxygen, particle radiation minutes deep-dielectric charging electrical discharges causing physical damage >100 keV electrons hours total ionizing dose performance degradation loss of function loss of mission >100 keV: trapped protons and electrons, solar protons hours non-ionizing dose degradation of optical components and solar cells > 1 MeV: trapped protons, solar protons, neutrons days single event effects data corruption noise on images interruption of service loss of s/c > 10 MeV/n: trapped protons, solar protons, solar heavy ions, GCR heavy ions, neutrons days

21. 21 http://www.aero.org/publications/crosslink/summer2003/02_table1.html

22. 22 Solar Storm: flare, SPE, CME Enhanced EM Radiation (X, EUV, radio,  ) Arrival time: 8 min Effect duration: 1-2 hrs High Energy Charged Particles (p + : 10 MeV – 20 GeV) Arrival time: 15 min – few hours Effect duration: hours - days Enhanced B Field/ Plasma Clouds Arrival time: 2 – 4 days Effect duration: days high-altitude hf radio blackout high-altitude aircraft radiation satellite desorientation s/c electronics damage s/c solar panel degradation false sensor readings launch payload failure human cell damage ozon layer depletion hf radio blackout satcom inteference radar interference image interference satellite drag hf radio blackout shift of outer radiation belt s/c charging radar false targets satcom interference oil and gas pipeline corrosion electrical power blackouts → induced currents → geomagnetic field distortion → increased radiation exposure → e - density in ionosphere → expansion atmosphere

23. 23 ‘Solar storm threat analysis’ by J.A. Marusek (http://www.breadandbutterscience.com/SSTA.pdf)http://www.breadandbutterscience.com/SSTA.pdf Threat matrix

24. 24 References.  E.G. Stassinopoulos et al., “A systematical global mapping of the radiation field at aviation altitudes, Space Weather, Vol. 1, No. 1, 1005, 2003.  Adams, Jr., et al., “A comprehensive table of ion stopping powers and ranges”, NRL Memorandum Report, 1987.  June, I., et al., “Proton Nonionising Enegy Loss (NIEL) for Device applications”, IEEE Transactions on Nuclear Science, Vol. 50, No. 6, Dec. 2003  June, I., et al., “Electron Nonionising Enegy Loss (NIEL) for Device applications”, IEEE Transactions on Nuclear Science, Vol. 56, No. 6, Dec. 2009  C.J. Mertens et al., “Geomagnetic influence on aircraft radiation exposure during a solar energetic particle event in october 2003, Space Weather 8(S03006): doi:10.1029/2009SW000487 (2010a)  G. P. Summers, Damage Correlation in Semiconductors Exposed to Gamma, Electron, and Proton Radiations, IEEE Trans. Nuc. Sci. 40, pp. 1300, 1993.

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