Notions sur l`interaction des photons avec la matière

µ
I(x0)x0
dx0
−dI =I(x0)−I(x0+dx0) = µI (x0)
(−)
I0x= 0 x
−dI
I=µdx0
−ˆI
I0
dI
I=µˆx
0
dx0
I(x) = I0e−µx
µ
σ
I(x) = I0e−nσx
µ=nσ
n A ρ
n=ρNA
A

Eγ=hν
Ee=Eγ−EL
EL
K
X
(∼)
σpe 'Z5m0c2
Eγn
n=(7
2Eγm0c2
1Eγm0c2
Z
Eγ'1
Eγ=hν p =Eγ/c
Eγ100
θ
E0
γ=Eγ
1 + Eγ
m0c2(1 −cos θ)

m0c2= 511
Ee=Eγ−E0
γ≈Eγ
σC'Z
Eγ
ln Eγ
0.1−10
Eγ>2m0c2
e+e−E=Eγ
e++e−→γ+γ
γ
Z2Eγm0c2
σcp '28
9Z2α3~c m0c22ln 183 Z−2 7
10
(>100 )
λ0
λcp =1
µcp
≈9
7λ0

(∼)
10 113
γ
α
10 +→7+α
I(x) = I0e−nσx