1
Radiation interaction with matter
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Outline
Introduction
Generalities
cross section
dE/dx
LET and NIEL
Proton
electrons
range, practical range
Ionising and non ionising dose
Conclusion
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Particles of interest
protons
[1MeV, 1GeV]
electrons
[10keV, 10 MeV]
hn
Photons
x, g
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ions
[1 MeV/uma, 1 GeV/uma]
4
GENERAL : Energy loss by unit path length
Assuming a straight line trajectory
dx
E - dE
E
dE
Interaction
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dE
dx
Nature of the medium
e-
e-
e-
e-
Si
Electrons act as a viscous
medium that slow down
incident particle
Si
e-
Si
e-
e-
Si
e-
e-
Nuclear
Reaction
a)
v
Si
e-
eSi
e-
e-
e-
Si
v
Si
e-
e-
e-
Si
e-
e-
e-
Si
e-
e-
e-
e-
e-
e-
Si
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e- silicium
e-
e-
Si
e-
e-
In addition, the probability to
encounter a nuclei is not
nul
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Incident particle
Incident particle
Si
v
e-
e-
Coulombic
Scattering
5,4 A
0,9 A
b)
Ionisation and Displacement for charged particles
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interaction with electrons
- ionisation
- Coulombic inelastic
scattering
interstitial
interaction with nuclei
- displacements
- elastic scattering
- nuclear reaction
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vacancy
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Total stopping power
nucleus
e-
dE dE
dE dE
dE dE
dE 
 
 
 

         

dx dx
 Total dx dx
 nuclear dx dx
 electronic dx  ray
 Total
 nuclear
 electronic
NIEL + phonon
Not negligeable for
low energy protons
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Bremsstrahlung
Not negligeable for
energetic electron
in heavy material
Ionising stopping power
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Proton stopping power
slowing down
of particles
Unit : MeV/mm or MeV/mg.cm2
1.E + 05
P ro to n
Io n s in S ilic o n
S ilicium
L ithium
2
L E T (M e V /g .c m )
1.E + 04
1.E + 03
1.E + 02
1.E + 01
1.E -01
1.E + 00
1.E + 01
E ne rg y (M e V )
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is proportional to density
dE/dx
is maximal when incident & target
particle are identical
r
B ra g g P e a k
1.E -02
dE/dx
1.E + 02
slowing down of particles
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Stopping power of electrons
1.E + 02
Hyd ro g e n
dE/dx
is proportional to specific gravity
dE/dx
is maximal when incident & target
particle are identical
A lum inium
2
L E T (M e V /g .c m )
Lead
r
B ra g g P e a k
E le c tro ns
1.E + 01
1.E + 00
1.E -02
1.E -01
1.E + 00
E ne rg y (M e V )
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1.E + 01
P
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Displacement damages
vacancy
interstitial
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Protons
P
Nuclear reaction
E
10 MeV
1 MeV
displacement
0,1 MeV
P
188 eV
Elastic scattering
- Coulombic scattering
- nuclear scattering
In silicon
1 eV
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No more displacement
Recoil energy < 25 eV
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Interaction of Charged particles with matter : electrons
E
Gamma
g - rays emission
Bremsstrahlung
1 MeV
Some displacements
- Coulombic scattering
250 keV
In silicon
No more displacement
Recoil energy < 25 eV
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Bremsstrahlung : Interaction of electromagnetic radiation
with matter
l
23
g - rays
E
1 pm 1 MeV
10 nm 100 eV
Gamma ray emission by
interaction with electric
field of the atom of the
target
Ia
Zincident Ztarget
Mincident
2
400 nm 3 eV
750 nm 1 eV
1 mm 10-3 eV
m
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Proton
Electron
negligeable Heavy material
large Mincident with large Ztarget
24
The range is deduced from the stopping power
depth
Range > depth
d is trib u tio n
120
80
p ractical ran g e
ran g e
40
0
0
0.5
1
1.5
2
100
80
d is trib u tio n
dx
D iffe re n tia l p a th le n g th
dE
 dE
T ra n s m is s io n ra te (% )

Al
13
1 MeV electron
beam
In te g r a te d p a th le n g th
range ( E ) 
1
27
Material surface
Range of particles
m ean
crossed
th ickn ess
Mean
penetration
depth
60
p ractical ran g e
40
ran g e
1 M e V e le c tro n in A l
20
0
0
0 .5
1
1 .5
A lu m in u m th ickn ess [m m ]
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2
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Range of protons & ions
Protons in different materials
Ions in silicon
1.E+00
1 .E +0 1
hydrogen
P ro to n
aluminum
1.E-01
1 .E +0 0
lead
S ilico n
L ithium
1 .E -0 1
Range (g/cm2)
2
R a n g e s (g /c m )
1.E-02
1.E-03
Protons
1.E-04
1 .E -0 2
1 .E -0 3
1 .E -0 4
Io ns in S ilic io n
1.E-05
1 .E -0 5
1.E-06
1.E-03
1 .E -0 6
1.E-02
1.E-01
1.E+00
Energy (MeV)
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1.E+01
1.E+02
1 .E -0 2
1 .E -0 1
1 .E +0 0
1 .E +0 1
E ne rg y (M e V )
1 .E +0 2
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Range of electrons
1.E+02
100
hydrogen
aluminum
1.E+01
Aluminum thickness (mm)
lead
Parcours (g/cm2)
1.E+00
1.E-01
Electrons
1.E-02
1.E-03
1.E-04
1.E-02
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Practical range
Practical range (10% transmission
rate)
Mean crossed thickness (50%
transmission rate)
Range
1
0.1
0.01
1.E-01
1.E+00
1.E+01
Energie (MeV)
1.E+02
1.E+03 0.001
0.01
0.1
Energy (MeV)
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1
10
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Order of magnitude
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trajectories
Aluminium
Proton (100 MeV)
100 MeV protons in Al
10 MeV electrons in Al
Bremsstrahlung
Tr ac e d'un ion c ar bone de 1 5 0 Me V dans du s ilic ium
Aluminium
1 E +0 0
1 E -0 1
84 MeV Carbon
in Silicon
1 E -0 2
5,99 µm
Electrons (1 MeV)
1 E -0 4
1E+14
1 E -0 5
1E+16
1 E -0 6
2 E+20
1 E -0 7
1 E -0 8
4E+20
3E+20
5E+20
8 E+20
1 E -0 9
1E+21
1 E -1 0
0
18
36
54
72
89
10 7
12 5
14 3
16 1 17 9
19 7
2 15 2 3 3 2 5 1 2 6 8 2 8 6 3 0 4 3 2 2 3 4 0 3 5 8 3 6 3
t h i c k n e s s ( µm )
150 M e V
90 M e V
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5 M eV
dire c tion de l'ion
1E+19
3 E +21
r ay ( g/c m ²)
1 E -0 3
Back-scattered electron
1 MeV electrons
in Al
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Ionising and non ionising dose
Dose is the averaged energy deposited by unit of mass :
Surface S
dx
h atoms/cm3
dna scattered particles
J/ kg = Gray
1 Gray = 100 rad
Flux F
Deposited energy
DE
Incident Number of particle
Dose 
Volume
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F  S  dE
S  dx  r
Mass
F
1 dE
r dx
 FF.
 LET
NIEL
Ionising Dose : Normaly incident protons
30
1200
do s e fo r 1 0
150 keV
+10
p/c m2
400 keV
1000
D o s e (G ra y )
800
30 kev
1 MeV
10 MeV
Due to straggling and
scattering
600
400
Compromise between
the increase of the LET
and the decrease of the
flux due to scattering
200
0
0 .0 0 0 0 1
0 .0 0 0 1
0 .0 0 1
0 .0 1
T h ic k n e s s (g /c m 2 )
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0 .1
1
31
27
Al
Al
13
120
d is trib u tio n
D iffe re n tia l p a th le n g th
Material surface
Ionising Dose : Normaly incident electrons
80
p rac tic al ran g e
ran g e
40
0
0
0.5
1
1.5
2
80
distrib ution
Transm ission rate (% )
Integr ated path le ngth
100
m e a n c ro s s e d th ic k n e s s
60
p ra c tic a l ra n g e
40
ra n g e
1 M e V e le c tro n in A l
Peack smoother
than for protons
as electrons are
largely scattered
20
0
0
0 .5
1
1 .5
A lu m in u m th ic k n e s s [m m ]
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2
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Ionising Dose : Normaly incident electrons + Bremsstrahlung
Electrons, incidence 30deg, 400keV,in aliminum
1.E+01
1.E+00
Bragg Peak
1.E-01
1.E-02
Dose enhancement
1.E-03
1.E-04
1.E-05
1.E-06
0.00001
gamma
Dose (Gy)
densite = 2.7 g/cm3
0.0001
0.001
0.01
0.1
Thickness (mm)
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1
10
100
1000
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Mission ionising dose : LEO, GEO
1.E+ 05
LEO O R BIT (S p o t)
T rap p ed elec tro ns
Infinite s lab
1.E +07
1.E+ 03
1.E+ 02
1.E+ 01
1.E+ 00
Total
1.E- 01
1.E +04
1.E +03
G EO O R BIT
1.E +02
1.E +01
Trapped electrons, AE8M in
S o lar m axim um
Infinite S lab
1.E +00
1.E- 03
1E -5
1.E +05
Trapped protons, AP 8M in
S olar flare P rotons, F eynman M in
1.E- 02
T rap p ed p ro to ns
1.E +06
D o se A l (G y /y ear)
D O S E A l (G ray s/y ear)
1.E+ 04
S o lar flare p ro to ns
1.E +08
1.E -01
1E -4
1E -3
1E -2
1E -1
1E +0
T hic knes s Al (g/c m2)
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1E +1
1E +2
1E-05 0.0001 0.001
0.01
0.1
1
Thickness (m m )
10
100
1000
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Mission ionising dose : GPS
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Conclusion
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)
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Conclusion
LET is used to quantify SEE effects (sSEU(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
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