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Radiation interaction with matter

1

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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

2

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Particles of interest

h

Photonsx,

protons[1MeV, 1GeV]

electrons[10keV, 10 MeV]

ions[1 MeV/uma, 1 GeV/uma]

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GENERAL : Energy loss by unit path length

4

dx

Interaction

dE

E - dEEdE

dx

Assuming a straight line trajectory

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Nature of the medium

Si

e-

e-

e-

Si

e-

e-

e-

Si

e-

e-

e-

SiSi

Si

e-

e-

e-

Si

e-

e-

e-

Si

e-

e-

e-

Si

e-

e-

e-

Si

e-

e-

e-

Si

e-

e-

e-

Si

e-

e-

e-

Si

e-

e-

e-

silicium

Incident particle

CoulombicScattering

v

v

v

Incident particle

Nuclear Reaction

Slo

win

g do

wn

5,4 A0,9 A

a) b)

Slo

win

g do

wn

Electrons act as a viscous medium that slow down incident particle

In addition, the probability to encounter a nuclei is not nul

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Ionisation and Displacement for charged particles

interaction with electrons

- ionisation- Coulombic inelastic

scattering

interaction with nuclei

- displacements - elastic scattering

- nuclear reaction

vacancy

interstitial

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Total stopping power 9

Not negligeable for energetic electronin heavy material

Not negligeable for low energy protons

e-nucleus Bremsstrahlung

NIEL + phonon Ionising stopping power

electronicnuclearTotal dx

dE

dx

dE

dx

dE

rayelectronicnuclearTotal dx

dE

dx

dE

dx

dE

dx

dE

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slowing down of particles

Proton stopping power

Unit : MeV/m or MeV/mg.cm2

12

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E-02 1.E-01 1.E+00 1.E+01 1.E+02

Energy (MeV)

LE

T (

Me

V/g

.cm

2 )

Proton

Silicium

Lithium

Ions in Silicon

Bragg Peak

dE/dx is proportional to density

dE/dx is maximal when incident & target particle are identical

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slowing down of particlesStopping power of electrons

1.E+00

1.E+01

1.E+02

1.E-02 1.E-01 1.E+00 1.E+01

Energy (MeV)

LE

T (

Me

V/g

.cm

2 )

Hydrogen

Aluminium

Lead

Electrons

Bragg Peak

dE/dx is proportional to specific gravity

dE/dx is maximal when incident & target particle are identical

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14

Displacement damages

P

interstitial

vacancy

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Protons

E

1 eV

0,1 MeV

1 MeV

188 eV

10 MeV

No more displacementRecoil energy < 25 eV

Elastic scattering- Coulombic scattering- nuclear scattering

Nuclear reaction

21

In silicon

P

Slow

ing down by ionisation

displacement

P

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Interaction of Charged particles with matter : electrons

- rays emissionBremsstrahlung

E

1 MeV

250 keV

No more displacementRecoil energy < 25 eV

- Coulombic scattering

Gamma

Some displacements

22

Slow

ing down by ionisation

In silicon

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Bremsstrahlung : Interaction of electromagnetic radiation with matter

- rays E

10-3 eV

m

1 eV

3 eV

100 eV

1 MeV

1 mm

750 nm

400 nm

10 nm

1 pm

23

Gamma ray emission by interaction with electric field of the atom of thetarget

Zincident Ztarget

Mincident

I 2

negligeable

large Mincident

Proton Electron

Heavy material

with large Ztarget

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Range of particles

The range is deduced from the stopping power

dE

dxdE

Erange 1

)(

24

range

depth

Al

1 MeV electron beam

0

40

80

120

0 0.5 1 1.5 2Dif

fere

nti

al p

ath

len

gth

d

istr

ibu

tio

n

range

practical range

0

20

40

60

80

100

0 0.5 1 1.5 2Aluminum thickness [mm]

Tran

smis

sio

n r

ate

(%)

Inte

gra

ted

pat

h l

eng

th

dis

trib

uti

on

1 MeV electron in Al rangepractical range

mean crossed thickness

Al27

13

Mat

eria

l sur

face

Range > depthMean penetration depth

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Range of protons & ions

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02

Energy (MeV)

Ran

ge (

g/cm

2 )

hydrogen

aluminum

lead

Protons

25

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E-02 1.E-01 1.E+00 1.E+01 1.E+02

Energy (MeV)

Ra

ng

es

(g/c

m2 )

Proton

Silicon

Lithium

Ions in Silicion

Ions in siliconProtons in different materials

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Range of electrons

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03

Energie (MeV)

Par

cour

s (g

/cm

2 )

hydrogen

aluminum

lead

Electrons

26

0.001

0.01

0.1

1

10

100

0.01 0.1 1 10

Energy (MeV)A

lum

inum

thic

knes

s (m

m)

Practical range

Practical range (10% transmissionrate)Mean crossed thickness (50%transmission rate)Range

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Order of magnitude27

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trajectories28

Aluminium Proton (100 MeV)

Aluminium

Electrons (1 MeV)

Back-scattered electron

10 MeV electrons in AlBremsstrahlung

100 MeV protons in Al

84 MeV Carbon in Silicon

1 MeV electrons in Al

1E-10

1E-09

1E-08

1E-07

1E-06

1E-05

1E-04

1E-03

1E-02

1E-01

1E+00

0 18 36 54 72 89 107 125 143 161 179 197 215 233 251 268 286 304 322 340 358 363

thickness (µm)

ray

(g/c

m²)

Trace d'un ion carbone de 150 MeV dans du silicium

direction de l'ion

150 MeV 5 MeV

1E+14

1E+16

1E+19

3E+20 4E+20 5E+20 1E+21

5,99 µm

90 MeV

2 E+20

8 E+20

3 E

+21

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Ionising and non ionising dose29

Dose is the averaged energy deposited by unit of mass :

J/ kg = Gray1 Gray = 100 rad

Flux

dx

Deposited energy E

Surface S atoms/cm3

dn scattered particles

Volume Mass

Incident Number of particle

LETdx

dE

dxS

dESDose

1

. NIEL

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Ionising Dose : Normaly incident protons

0

200

400

600

800

1000

1200

0.00001 0.0001 0.001 0.01 0.1 1

Thickness (g/cm2)

Do

se

(G

ray

)

30 kev

150 keV 400 keVdose for 10+10p/cm2

1 MeV

10 MeV

30

Due to straggling andscattering

Compromise betweenthe increase of the LET and the decrease of the flux due to scattering

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Al

0

40

80

120

0 0.5 1 1.5 2Dif

fere

nti

al

pa

th l

en

gth

dis

trib

uti

on

range

practical range

0

20

40

60

80

100

0 0.5 1 1.5 2Aluminum thickness [mm]

Tra

ns

mis

sio

n r

ate

(%

)

Inte

gra

ted

path

le

ng

th

dis

trib

uti

on

1 MeV electron in Al rangepractical range

mean crossed thickness

Al2713

Mat

eria

l sur

face

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

0.0 0.2 0.4 0.6 0.8 1.0 1.2

THICKNESS Al (g/cm2)

2,5 MeV

2,0 MeV

1,5 MeV

1,0 MeV

0,6 MeV

ELECTRONS IN ALUMINUM

(1E10 e/cm2 - normal incidence)

31

Ionising Dose : Normaly incident electrons

Peack smoother than for protonsas electrons arelargely scattered

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Electrons, incidence 30deg, 400keV,in aliminum

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

0.00001 0.0001 0.001 0.01 0.1 1 10 100 1000

Thickness (mm)

Do

se

(G

y)

densite = 2.7 g/cm3

32

Ionising Dose : Normaly incident electrons + Bremsstrahlung

Bragg Peak

Dose enhancementga

mm

a

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Mission ionising dose : LEO, GEO33

LEO ORBIT (Spot)Infinite slab

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1E-5 1E-4 1E-3 1E-2 1E-1 1E+0 1E+1 1E+2

Thickness Al (g/cm2)

DO

SE

Al (

Gra

ys/y

ear)

Total

Trapped protons, AP8Min

Solar flare Protons, Feynman Min

Trapped electrons, AE8Min

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

1E-05 0.0001 0.001 0.01 0.1 1 10 100 1000

Thickness (mm)D

ose

Al (

Gy/

year

)

Solar flare protons

Trapped electrons

Trapped protons

GEO ORBITSolar maximum

Infinite Slab

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YEAR AVERAGED DOSE FOR GPS ORBIT

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

0.001 0.01 0.1 1 10 100

THICKNESS Al (g/cm2)

GEANT, AE8Min : électrons

Orbit : 20000 km, 55° - Solar Minimum

GEANT 4 calculationDouble infinite slab

34

Mission ionising dose : GPS

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Conclusion37

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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Conclusion38

LET is used to quantify SEE effects (SEU(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 quantifymany degradations induced by space radiations