space radiation environmentmagnetic storms •solar wind disturbs the current systems in the...
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Space Radiation Environment
Behcet ALPATINFN -Perugia, Italy
IV Corso di Formazione INFN su “Qualità e Progettazione di Sistema per Esperimenti di Fisica nello Spazio e agli
Acceleratori” 20-22 Ottobre , 2010, Assisi
B.Alpat, Corso di Formazione INFN, 20-22- Ottobre, 2010, Assisi2
SQ Constraints
• The following constraints shall be taken into account according to the mission:– resistance to corrosion,
– resistance to mechanical load (dynamic or static),
– resistance and performance in vacuum,
– performance in microgravity,
– resistance to radiation,
– resistance to thermal cycling,
– resistance to fluids according to mission requirements,
– resistance to other conditions specific to the mission (atomic oxygen, offgassing, flammability, odour, etc...).
– resistance to combined actions of the environment and loads (stress corrosion cracking, thermoelastic behavior, cold welding,...).
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Radiation Hardness Assurance
(RHA)
• The organization, documentation and procedures developed and applied to assure that a system can operate in a specified radiation environment
• These activities may occur at the system, sub-system, module/board and piece part levels
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Critical Parameters for
Mission Definition for
Radiation Predictions
• When and how long the mission will fly • Where the mission will fly • When the systems are deployed • What systems must operate during worst
case environment conditions • What systems are critical to mission
success • Amount of shielding surrounding devices
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B.Alpat, Corso di Formazione INFN, 20-22- Ottobre, 2010, Assisi6
Components of the Natural
Environment
• Solar Particle Events– Protons & Heavier Ions
• Transient– Galactic Cosmic Rays
• Protons & Heavier Ions
• Trapped– Electrons, Protons, & Heavier Ions
• Atmospheric & Terrestrial Secondaries– Neutrons
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Radiation & Effects
• Total Ionising Dose– Cumulative long term
ionising damage due to protons & electrons
• Displacement Damage– Cumulative long term
non-ionising damage due to protons, electrons, & neutrons
• Single Event Effects– Event caused by a
single charged particle -heavy ions & protons for some devices
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Sun
• Dominates theRadiationEnvironment– Source
– Modulator
• Structure– Photosphere
– Chromosphere
– Corona
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Solar Flares
• Sudden BrighteningNear Sunspots
• Solar System’ sLargest ExplosiveEvents
• Particles AcceleratedDirectly by Event
• Heavy Ion Rich SolarEvents
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Coronal Mass Ejection
• Observed byLASCO C2 on 2000.
• Bubble of Gas & Magnetic Field
• Ejects ~10 17 grams of Matter (mostly protons and electrons)
• Shock Wave AcceleratesParticles to Millions of km/hr
• Associated with Magnetic Storms
• Proton Rich Solar Events
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TIROS Measurements of
Protons
Day Before Coronal Mass Ejection
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TIROS Measurements of
Protons (cont’d)
November 6, 1997 Coronal Mass Ejection
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Eruptive Prominance
• Erupting prominances when Earthward directed can affect communications, navigation systems even power grids, while also producing auroras visible in the night skies
Prominance 24 Juy 1999 (extends over 35 Earths out from Sun)
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Coronal Holes
• Darker/cooler zone of corona
• Observed by X-ray telescope on Skylab
• Fast moving solar wind pass through (magnetic fields lines)
• Contribute to flux modulation in outer belts
From G.Berger SERESSA09
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Solar Wind
• Stream of Charged Particles from Sun’ sCorona– Electrons– Protons Density ~ 1 - 30 / cm 3– 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
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Aurora
• Particles stream down onmagnetic field lines from the geomagnetic tail forming an auroral belt
• Electrons collide withatmospheric gases
• Electrons give energy to atoms and molecules which emit energy as light
• Oxygen ---> GreenNitrogen ---> Red
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Solar Wind Density & VelocityD
ensi
ty (
#/c
m3)
Velo
city
(km
/s)
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Solar Activity: Cyclic
Variation
• Sunspot Cycle Discovered in mid 1800s
• Used as Indicator of Solar Activity
• Increased Solar Activity Results in:– Increased Rate of CME
– Increased Rate of Solar Flares
– Increased Rate of Magnetic Storms
– Increased Levels of Electrons in Van Allen Belts
– Decreased Levels of Protons in Van Allen Belts
– Increased Incidence of New Belt Formation
– Decreased Levels of Galactic Cosmic Rays
– Increased Rate of Solar Particle Events
• Effects on Climate?
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Sunspot Cycle
Length Varies from 9 – 13 Years, 7 years Solar Maximum, 4 Years Solar
Minimum
Su
nsp
ot N
um
ber
s
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Sunspot CycleS
un
spo
t N
um
ber
s
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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)
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Solar Particle Events
• Poor Correlation with Solar Flares• Strong Correlation with Coronal Mass
Ejections– No Fundamental Association with Flares– Transient Shock Wave Disturbances in the
Solar Wind– Large Geomagnetic Storms– Large Particle Events
Solar Particle Events
Rapid onset times (minutes), with durations up to hours or days
Essentially unpredictable, however generally coincide with solar maximum periods
Proton energies up to ~100s ofMeV, sometimes GeV range
Integral fluence up to ~109 –1010 p/cm2 (>1 MeV)
Some contribution from heavierions and e-
In the main phase of an event,particle fluxes isotropic
In space mission design andoperational context, treated withstatistical models (JPL-91, ESP,Rosenqvist) and “SpaceWeather” updates
From P.Nieminen, CERN, Februray 2010
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B.Alpat, Corso di Formazione INFN, 20-22- Ottobre, 2010, Assisi24
14 July 2000, Protons and X-
Rays
From G.Berger SERESSA09
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Sunspot Cycle with Solar
Proton Events
Proton Event Fluences
Years
Pro
ton
s (#
/cm
2)
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Solar Protons:Orbits
Proton Levels Predicted by CREME96
Pro
ton
s (#
/cm
2/s
ec/M
eV)
Energy (MeV)
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Magnetosphere
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Magnetic Storms
• Solar Wind Disturbs the CurrentSystems in the Magnetosphere
• Major Storms Probably the Result of CMEs– Must Be Pointed Toward Earth– Strongest Arrive with Interplanetary
Magnetic Field Oriented South
• Cause Increase in Rate & Intensity ofMagnetic Sub-storms in the Geotail
B.Alpat, Corso di Formazione INFN, 20-22- Ottobre, 2010, Assisi29
Effects of Solar Storms
• Power Black-outs on Earth• Block Some Radio Communication
– Disturbs electrically charged gases in the ionosphere
• Interfere with Cellular Phone Systems– Ionospheric disturbances & satellite system
failures
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Effects of Solar Storms
(cont’d)
• Interfere with GPS Navigation (Ships & Airplanes)
• Trigger Phantom Commands on Spacecraft
• Increased Atmospheric Drag on Low Earth Orbit (LEO) Satellites
• Increased Protons & Heavy Ion Particle Counts
• “Pump Up” the Van Allen Belts
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Discovery of Galactic
Cosmic Rays - 1913
• Electroscope Experiments– Dissipation of Charge on Leaves?– Emissions from Materials on Earth– “Clean” Instruments Did Not Eliminate Dissipation
• Hess– Balloon Experiments with Electroscopes– Hypothesis: Background Radiation Will Disappear
with Increasing Altitude– > 10,000 feet - Background Increased with Altitude– Named “Cosmic Rays” by Hess
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All Particle Spectrum and
Composition of Cosmic Rays
•All stable elements ofperiodic table are presentin CR
•Abundances equal tothose of solar system
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Particle Composition at Low
Energies
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GCRs: Solar Modulation
• CNO-24 hour mean exposure
CN
O (
#/c
m2/s
ter/
s/M
eV/n
)
Date
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GCRs:Shielded Fluences-Fe
• Interplanetary,CREME96, Solar Minimum
Part
icle
s (#
/cm
2/d
ay/M
eV/n
)
Energy (MeV/n)
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GCRs:Shielded Fluences-Fe
• CREME96, Solar Minimum, 100 mils (2.54mm) Al
Part
icle
s (#
/cm
2/d
ay/M
eV/n
)
Energy (MeV/n)
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Trapped Radiation
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Discovery of Radiation Belts
(Trapped Radiation-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 DuringMagnetic Storms– March 1991 Storm - Increases Were Long Term
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Trapped Particle Motions
Spiral, Bounce, Drift
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Van Allen Belts
High Latitude Horns
Outer Belt
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Proton & Electron
Intensities
AP-8 Model AE-8 Model
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TIROS/NOAA Trapped Protons
Radio
Flu
x F
10
.7
Solar Cycle Variation: 80-215 MeV Protons
Pro
ton F
lux (
#/c
m2/s
ec)
Date
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Activity in the Slot Region-
SAMPEX
SAMPEX/P1ADC: Electrons E > 0.4 MeV
L-S
hell
Day(1992)
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SRAM Upset Rates on
CRUX/APEX
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Terrestrial Radiation Sources
• Man-made• Natural Emissions from Earth Materials
– Package Contamination
• Cosmic Rays - Particle Showers
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Terrestrial Cosmic Rays
• Particles That Hit the Earth from Outer Space• Need > 1 GeV to Penetrate to Sea Level• Fewer Than 1% Are Primary• Mostly 3rd to 7th Generation Cascade Particles• Search for Cause of Interference on Laboratory• Instruments in Early 1900s
– Led to Discovery of Cosmic Rays by Hess
• Induce SEUs: Neutrons + Protons + Pions
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The process begins in space with primary galactic cosmic rays
entering the atmosphere after passing through the heliosphere
(solar modulation) and geomagnetic field (rigidity cutoff).
Most of these primaries are energetic enough to produce
a nuclear or high energy interaction initiating a cascade
of particles through the atmosphere.
As the ensemble of cascades
develop the particle density and
the particle type distribution varies
with atmospheric depth as shown
in the Figure.
The passage of each particle type
through atmosphere is
determined by different interaction
channels. The dominate
interaction depends on particle
type, energy and material.
Above energies of 100MeV muons are the dominate species at
sea-level, however when considering all energies neutrons
dominate in numbers.
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Neutrons
• 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
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Neutron Environment(Normand et al.)
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Neutron Flux MeasurementsN
orm
aliz
ed t
o P
eak
Altitude (feet)
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AM9114 4K NMOS Error Rates
Protons Neutrons Muons Pions Pions
>100 MeV >10 MeV (Stopping) >100 MeV (Stopping)
Pre
dic
ted
Err
ors
/Dev
ice/
s
Predicted Error Rates at Two Altitudes
52
Involves 3 different quantities;
1. The cross section of the device,often determined empirically;
2. The distribution of particlesexpected in the spaceenvironment, which depends onassumptions about solar flareactivity, radiation belt activity,and shielding;
3. The critical charge, sensitive areaand sensitive volume associatedwith the SEE phenomenon ofinterest.
Expected SEE Rate Calculation
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B.Alpat, "Space Radiation and its Effects" Course, ASELSAN, July 14-16th, 201053
Simulations of the
Space Radiation
Environment
• From G.Santin
Protons, some ions, electrons, neutrons,
gamma rays, X-rays…
Softer spectrum
Event driven – occasional high fluxes over short
periods.
Solar radiation Electrons ~< 10 MeV
Protons ~< 102 MeV
Trapped radiation
Sourc
es
Protons and Ions
<E> ~ 1 GeV, Emax > 1021 eV
Continuous low intensity
(Extra) Galactic and
anomalous Cosmic Rays
Effects
Single Event Effects
(SE Upset, SE Latchup, …)
Degradation
(Ionisation, displacement,…)
Effects in components
Signal, Background
(Spurious signals, Detector overload,…)
Charging
(internal, interferences, …)
Effects to science detectors
Dose (dose equivalent) and dose rate in
manned space flights
Radiobiological effects
Threats to life
Ground tests
Extrapolation to real life in space
Cheaper than accelerator tests
Mission design
Goals
Particle signal extraction
Background
Degradation
Science analyses
Simulation of the emission and the
propagation of radiation in space
Environment models
From G.Santin
54
Radiation Environment Simulation
Current tools include:
SPENVIS – models of space environment & basic effects analysis (ESA/BIRA)
CREME96 – Cosmic Ray/SEU analysis (NRL)
SIREST – space environment analysis for Shuttle missions (NASA/LaRC)
SEDAT (Space Environment Data Analysis Tool) – databases of space environment data & tools for analysis. (ESA/RAL)
ESABASE/Radiation Space Systems Analyser
…
GEANT4Physics models
– Scientific Exploration,
Manned space flight:
– Low En EM, Ion hadronics
Engineering tools
– PlanetoCosmics (mg cut-off)
– SSAT (Ray-Tracing)
– MULASSIS (1D shielding)
– GEMAT (micro-dosimetry)
– NIEL (Displacement Damage)
– Reverse MC
– GRAS ( 3D, multi-purpose analysis framework)Interfaces
– Materials
– GDML
– CAD geometries
– SPENVISB.Alpat, Corso di Formazione INFN, 20-22- Ottobre, 2010, Assisi
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Radiation Environment Simulation
Particle fluxes simulated using SPENVIS, CREME96, AF-GEOSPACE
Effects on devices simulated using GEANT4, GRAS, FLUKA
By simulating both diffuse and location dependent contributions (like Particles Trapped by Geomagnetic field) we are able to estimate the effects on average and in the Worst Case Scenario.
The SPENVIS, ESA's Space Environment Information System, is basedon a WWW interface to models of the space environment and its effects,including the natural radiation belts, solar energetic particles, cosmicrays, plasmas, gases, and "micro-particles”.Th:user should provide to SPENVIS as input several information such as,-The mission parameters,- the space weather conditions,- the type of particles for which the SEE effects can be estimated,- DUT parameteres (i.e. dimensions, bulk material, layout etc.)shielding configurations,cross section versus LET values including saturated cross section and -LET threshold values deriving from Weibull fit
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B.Alpat, "Space Radiation and its Effects" Course, ASELSAN, July 14-16th, 201056
FRAM TEST REPORT AND
MITIGATION SUGGESTED
• FRAM -> SEE_Rates_and_Mitigation3-2.pdf
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Useful Links
• SPENVIS http://www.spenvis.oma.be/spenvis/
• CREME96 https://creme96.nrl.navy.mil/
• GEANT4-Space http://geant4.esa.int/
• ESA-ESCC https://spacecomponents.org/
• ESA- Space Weather http://esaspaceweather.net/spweather/BACKGROUND/index.html
• NASA-RadHome http://radhome.gsfc.nasa.gov/radhome/Nat_Space_Rad_Tech.htm
• NASA Standards http://standards.nasa.gov/
• MIL Standards http://assist.daps.dla.mil/quicksearch/
• JEDEC Standars: www.jedec.org
ESA Space Environments and Effects http://space-env.esa.int/
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End (Space Radiation Environment)