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Janet Barth NASA/Goddard Space Flight Center

Military and Aerospace Applications of Programmable Devices and Technologies Conference Radiation Environments. Janet Barth NASA/Goddard Space Flight Center. Greenbelt, Maryland September 1998. The Radiation Environment. Galactic Cosmic Rays. Solar Protons & Heavy Ions. Trapped Particles.

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Janet Barth NASA/Goddard Space Flight Center

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  1. Military and Aerospace Applications ofProgrammable Devices and Technologies ConferenceRadiation Environments Janet Barth NASA/Goddard Space Flight Center Greenbelt, Maryland September 1998

  2. The Radiation Environment Galactic Cosmic Rays Solar Protons & Heavy Ions Trapped Particles Nikkei Science, Inc. of Japan, by K. Endo

  3. Components of the Natural Environment • Transient • Galactic Cosmic Rays • Hydrogen & Heavier Ions • Solar Particle Events • Protons & Heavier Ions • Trapped • Electrons, Protons, & Heavier Ions • Atmospheric & Terrestrial Secondaries • Neutrons

  4. Effects • Displacement Damage • Protons • Electrons • Total Ionizing Dose • Trapped Protons & Electrons • Solar Protons • Single Event Effects • Protons • Trapped • Solar • Heavier Ions • Galactic Cosmic Rays • Solar Events • Neutrons

  5. The Sun Transient Particles Galactic Cosmic Rays Solar Particle Events Trapped Particles Atmospheric & Terrestrial Particles Nuclear Weapons Environment Summary Outline

  6. Sun Source Modulator Protons Galactic Cosmic Rays Atmospheric Neutrons Heavier Ions Trapped Particles Trapped Particles Sun:Dominates the Environment

  7. Solar Wind • Stream of Charged Particles from Sun’s Corona • Electrons • Protons • Heavy Ions • Magnetized Plasma • Detected Out to 10 billion km from Earth by Pioneer 10 • Velocity ~ 300 - 900 km/s • Energy ~ .5 - 2.0 keV/nuc  Density ~ 1 - 30 / cm3

  8. Coronal Mass Ejections Particles Accelerated by Shock Wave Largest Proton Events Decay of X-Ray Emission Occurs Over Several Hours Large Distribution in Solar Longitude Gradual Events Holloman AFB/SOON

  9. Solar Flares Particles Accelerated Directly Heavy Ion Rich Sharp Peak in X-Ray Emission Concentrated Solar Longitude Distribution Impulsive Events

  10. 300 250 200 150 100 50 0 1947 1997 Sunspot Cycle after Lund Observatory Cycle 19 Cycle 20 Cycle 21 Cycle 22 Cycle 18 Sunspot Numbers Years Length Varies from 9 - 13 Years 7 Years Solar Maximum, 4 Years Solar Minimum

  11. 200 100 80 150 60 100 40 50 20 0 0 1930 1940 1950 1960 1970 1980 1990 Sunspot Cycle with Magnetic Storms Sunspots & Magnetic Storm Days # of Days with Ap > 4 Sunspot Number Annual Sunspot Number Annual Number of Days with Ap>4

  12. Galactic Cosmic Ray Ions • All Elements in Periodic Table • Energies in GeV • Found Everywhere in Interplanetary Space • Omnidirectional • Mostly Fully Ionized • Cyclic Variation in Fluence Levels • Lowest Levels = Solar Maximum Peak • Highest Levels = Lowest Point in Solar Minimum • Single Event Effects Hazard • Model: CREME96

  13. GCRs: Nuclear Composition Energy = 2 GeV/n, Normalized to Silicon = 106 H He C O Si Fe Relative Flux (Si = 106) Zr Pt Ba Pb Individual Elements Even-Z Elements Elemental Groups Nuclear Charge (Z)

  14. GCRs: Solar Modulation CNO - 24 Hour Averaged Mean Exposure Flux Energy = 25-250 MeV/n IMP-8 CNO (#/cm2/ster/s/MeV/n) Date

  15. GCRs: Shielded Fluences - Fe Interplanetary, CREME 96, Solar Minimum Particles (#/cm2/day/MeV/n) Energy (MeV/n)

  16. momentum charge 2 3 4 5 6 7 Magnetic Rigidity Total Energy Required to Penetrate the Magnetosphere H 48 MeV 87 MeV 173 MeV 284 MeV 987 MeV Magnetic Equator 2900 MeV 1147 MeV/n 313 MeV/n 109 MeV/n 46 MeV/n 23 MeV/n 12 MeV/n Z > 1 after Stassinopoulos

  17. GCRs: Shielded Fluences - Fe CREME 96, Solar Minimum, 100 mils (2.54 mm) Al Particles (#/cm2/day/MeV/nuc) Energy (MeV/nuc)

  18. GCRs: Integral LET Spectra CREME 96, Solar Minimum, 100 mils (2.54 mm) Al Z = 2 - 92 LET Fluence (#/cm2/day) LET (MeV-cm2/mg)

  19. Solar Particle Events • Increased Levels of Protons & Heavier Ions • Energies • Protons - 100s of MeV • Heavier Ions - 100s of GeV • Abundances Dependent on Radial Distance from Sun • Partially Ionized - Greater Ability to Penetrate Magnetosphere • Number & Intensity of Events Increases Dramatically During Solar Maximum • Models • Dose - SOLPRO, JPL, Xapsos/NRL • Single Event Effects - CREME96 (Protons & Heavier Ions)

  20. Sunspot Cycle with Solar Proton Events Proton Event Fluences Protons (#/cm2) Year

  21. Solar Proton Event - October 1989 Protons & Electrons - Magnetic Field 99% Worst Case Event Counts/cm2/s/ster/MeV nT GOES Space Environment Monitor

  22. Proton Event Spectra - Cycle 22 Total Integral Proton Fluence Proton Fluence (#/cm2/event) Energy (> MeV)

  23. TIROS Measurement of Protons November 7, 1997 Coronal Mass Ejection H= 870/870 km

  24. TIROS Measurement of Protons Day After Coronal Mass Ejection H= 870/870 km

  25. Solar Protons: Orbits Proton Levels Predicted by CREME 96 Averaged Over Worst Day Protons (#/cm2/sec/MeV) Energy (MeV)

  26. Effect of Shielding on Heavy Ions Transient Particles Unattenuated by the Magnetosphere CREME96 Fluence (#/cm2/s) LET (MeV-cm2/mg)

  27. SEU Rate Increases During Solar Events Observation from UoSat-2 & Meteosat-3: EDAC was able to handle increased rates.

  28. Trapped Radiation Trapped Particles Protons, Electrons, Heavy Ions Nikkei Science, Inc. of Japan, by K. Endo

  29. Van Allen Belts Outer Zone Inner Zone Heavy Ions SAMPEX/NASA

  30. Trapped - Van Allen Belts • Omnidirectional • Components • Protons: E ~ .04 - 500 MeV • Electrons: E ~ .04 - 7(?) MeV • Heavier Ions: Low E - Non-problem for Electronics • Location of Peak Levels Depends on Energy • Average Counts Vary Slowly with the Solar Cycle • Location of Populations Shifts with Time • Counts Can Increase by Orders of Magnitude During Magnetic Storms • March 1991 Storm - Increases Were Long Term

  31. Trapped Particle Models • NASA AP-8 & AE-8 • Air Force CRRES & APEX Models • CRRESPRO, CRRESELE, CRRESRAD & APEXRAD • New Models - NASA Space Environment and Effects Program • Low Altitude Model - < 1000 km • Boeing • Based on TIROS Data • Extended to Higher Altitudes • Will Combine CRRES and TIROS Data

  32. 104 250 200 103 150 102 100 101 50 1976 1980 1984 1988 1992 1996 TIROS/NOAA Trapped Protons Solar Cycle Variation: 80-215 MeV Protons B/Bmin=1.0 L=1.20 L=1.18 L=1.16 Proton Flux (#/cm2/s) Radio Flux F 10.7 L=1.14 Date Huston et al.

  33. 6 4 2 1990 1991 1992 March Magnetic Storms - Hipparcos Star Mapper - Radiation Background L-Shell 4-Day, 9-Orbit Averages Daly, et al.

  34. CRRES - Measured Proton Belt AF Phillips Laboratory, SPD/GD

  35. Trapped Protons - 800 km Protons E > 30 MeV, Solar Max Protons/cm2/sec Latitude (deg) Longitude (deg)

  36. Trapped Electrons - 1000 km Integral Electron Flux Contours E > .5 MeV

  37. SRAM Upset Rates on CRUX/APEX

  38. AP8 - MAX Spectra Integral Proton Fluences • Energy Range • .04 - 500 MeV • Range in Al: • 30 MeV ~ .17 inch • Effects: • Total Dose • Single Event Effects • Solar Cell Damage Fluence (#/cm2/day) Energy (>MeV)

  39. Trapped Proton Predictions I=90 deg, H=1000/1000 km, Solar Minimum Protons (#/cm2/s) Energy (> MeV)

  40. AE-8 - MAX Spectra Integral Electron Fluences • Energy Range • .04 - 7 MeV • Range in Al: • Effects: • Total Dose • Surface Charging • Deep Dielectric Charging • Solar Cell Damage Fluence (#/cm2/day) Energy (>MeV)

  41. Interactions in the Atmosphere IBM Journal of Research & Development Terrestrial Cosmic Rays and Soft Errors

  42. Neutrons & Pions • Source - Secondary Products of Particle Cascades • Spacecraft Materials • Galactic Comic Ray Collisions with Atmospheric O & N • Single Event Upset Hazard • Ground Level in Large Memory Banks • Avionics • Low Earth Orbits - Shuttle • First Recognized as Problem in 1980s • Models • Atmospheric - Boeing & Wilson-Nealy • Ground - Empirical

  43. Neutron Environment Normand et al.                         1,000,000 feet 330 km Shuttle  Primary Cosmic Rays  Neutrons Secondary Cosmic Rays 150,000 feet 50,000 m Top of Atmosphere Peak Neutron Flux 60,000 feet 20,000 m  ~ 35,000 feet 10,000 m N,O Aircraft   Ground ~ 1/500 of Peak Flux

  44. Neutron Models: Flux vs. Altitude 1-10 MeV Atmospheric Neutron Flux 1-10 MeV Neutron Flux (n/cm2/s) Altitude ( Thousands of feet)

  45. Neutron Model: Flux vs. Latitude 1-10 MeV Atmospheric Neutron Flux 1-10 MeV Neutron Flux (n/cm2/s) Averaged Over Longitude Latitude (deg N)

  46. Neutron Model: Flux vs. Energy Differential Neutron Flux - Atmospheric Differential Flux (n/cm2/s/MeV) Energy (MeV)

  47. Terrestrial Cosmic Rays

  48. 8 No Electronic Defect 6 Normal Hard Fails 4 2 0 Average U.S. Above 2600 ft Above 5000 ft Altitude Dependence of Terrestrial Effects Repairs of Memory Modules Normalized Number of Failures From IBM Data Systems/1984

  49. Nuclear Weapons Effects G. Welles Still Army Research Laboratory

  50. Nuclear Weapons Environment > 1014 n/s > 108 rads(si)/s

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