Space Radiation Effects
Tutorial
E. De Donder (BIRA)
23/03/2012 at ROB
 www.spenvis.oma.be
1
Outline
1.
2.
General overview picture
Radiation environment




3.
Radiation effects




4.
GCR particles
Solar particles
Trapped particles
Secondary particles
Total Ionizing Dose (TID)
Displacement Damage (DDD)
Single Event Effects (SEE)
S/c charging
Solar storm threat-matrix
2
Radiation environment
Plasma environment
Neutral environment
+ drag
Microparticle environment
3
Radiation environment (1/4): GCR particles
protons and heavy ions (Z>1, mostly fully ionized)
E ~ 0.01 – 103 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.




GCR H & Fe fluxes at LEO, MEO, GEO and GTO (model: ISO 15390 sol. min.)
1.00E+01
LEO
MEO
GEO
GTO
1.00E+00
1.00E-01
1.00E-02
2
Differential flux (/m /sr/s/(MeV/n))
H
Magnetic rigidity = momentum per charge
1.00E-03
Fe
1.00E-04
Energy required to penetrate Earth’s magnetic field
(Stassinopoulos et al., 2003)
1.00E-05
1.00E-06
SPENVIS-4.5
1.00E-07
1
10
100
1000
10000
100000
E (MeV/n)
4
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)
CREME-96 Solar Flare "Worst Day" model (Oct. 1989)
1.0E+10
LEO
MEO
GEO
GTO
1.0E+09
H
Differential Flux (/m2/sr/s/(MeV/n))
1.0E+08
1.0E+07
1.0E+06
1.0E+05
Fe
1.0E+04
1.0E+03
1.0E+02
1.0E+01
1.0E+00
1.0E-01
1.0E-02
1.0E-03
1.0E-04
0.1
SPENVIS -4.5
1
10
100
1000
E (MeV/n)
5
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
SPENVIS – 4.5
E.J. Daly, 1996
6
AP-8 proton fluxes (full lines) and AE-8 electron fluxes (dotted lines) at sol. maximum
1.0E+12
LEO
MEO
GEO
GTO
1.0E+11
1.0E+10
Differential flux (/m2/s/sr/MeV)
1.0E+09
1.0E+08
1.0E+07
1.0E+06
1.0E+05
1.0E+04
1.0E+03
1.0E+02
1.0E+01
1.0E+00
1.0E-01
1.0E-02
1.0E-03
1.0E-04
0.01
SPENVIS -4.5
0.1
1
10
100
1000
E (MeV)
7
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.
8
→ interaction with atmosphere
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)
9
MIT OpenCourseWare
10
Radiation Effects
Energy deposition → Dose in rads (M) or Gy: dE/dm
Space environment dose rate ~10-4 – 10-2 rad/s → low
X fluence
Ionisation Dose
LET (linear energy transfer)
Non-ionisation Dose
NIEL (non-ionising energy loss)
Long-term effects
→ degradation of performance
Short-term effects
→ soft and hard errors
11
LET  f(E)
MZ2
E
(Adams et al., 1987)
Summers, 1993.
12
Radiation Effects (1/4): Total Ionizing Dose (TID)
▪
cumulative long term ionizing damage due to the production of electron – hole pairs

effects:
- build up of charges/defects → device degradation
(e.g. Vth shift and increasing leakage currents)
- DNA damage
▪
main source:
> 0.1 MeV protons (trapped & solar), electrons (trapped)
13
Radiation Effects (2/4): Displacement Damage Dose (DDD)
▪
cumulative long term non-ionizing damage due to the production of Frenkel pairs (vacancies and
interstitials)

effects:
lattice defects → parametric degradation (optical devices) like Pout
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
14
SOHO’s Solar Array Degradation History
Solar array degradation: Net loss in two week period 1.1%
15
Radiation Effects (3/4): Single Event Effect (SEE)
▪
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
charge ~Z2
H. Becker, et al, IEEE Trans. Nucl. Sci., 49(3082), 2002
16
SOHO image: “snowing on 14 July 2000
October 1989 event
UoSAT-2 ( polar orbit of altitude about 700km)
17
Radiation Effects (4/4): S/c charging
▪
accumulation of electric charge on s/c surface from natural space plasma → surface
charging
–
▪
accumulation of electric charge on internal dielectrics from penetrating high-energy
electrons → internal dielectric charging
–
▪
Main source : 0.01 – 100 keV electrons
Main source: > 100 keV electrons (trapped) - “Killer electrons”
effects:
(breakdown) discharges
18
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
Surface damage in a C2 MOS Capacitor (Image from JPL)
High speed solar wind and killer electrons
19
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
20
http://www.aero.org/publications/crosslink/summer2003/02_table1.html
21
Solar Storm: flare, SPE, CME
Enhanced EM Radiation
(X, EUV, radio, g)
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
→ e- density in ionosphere
→ expansion atmosphere
→ increased radiation exposure
→ induced currents
→ geomagnetic field distortion
• 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
• shift of outer radiation belt
• s/c charging
• radar false targets
• satcom interference
• oil and gas pipeline corrosion
• electrical power blackouts
• hf radio blackout
• satcom inteference
• radar interference
• image interference
• satellite drag
22
Threat matrix
Threat
Flare
SPE
CME
Induced current
power plant outage
oil and gas pipelines
long distant communication lines
Geomagnetic field distortions
transient distortion
magnetic pulses
Radiation exposure
humans
s/c electronics
air and ground based electronics
Ionospheric Reflectivity and Scintillations
communication
radar
navigation
Other atmospheric effects
aurora
atmospheric envelope expansion
shifting radiation belts
ozon layer depletion
‘Solar storm threat analysis’ by J.A. Marusek (http://www.breadandbutterscience.com/SSTA.pdf)
23
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.
24
25