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Air Kerma-rate constant Γ
δ
E,
tr
E
4
1
α
δ
ρ
µ
⋅ ⋅
π
=Γ
∑
⋅ ⋅
⋅
=
i
E,
tr
i
i
i
En
4
1
Γ
α
δ
ρ
μ
π
E,
tr
α
ρ
µ
Γ
δ
for
137
Cs = 0.0771 µGy h
-1
MBq
-1
m²
Γ
δ
for
60
Co = 0.3059 µGy h
-1
MBq
-1
m²
Γ
δ
for
60
Co is ≈ 4x of that of
137
Cs
E
E for
60
Co is ca. double of that of
137
Cs ?
60
Co: 2.0 photons per decay/disintegration
137
Cs: 0.9 photons per decay/disintegration