Introduction to Nuclear reactions

Differential cross section, σ(θ)
Α cross section per solid angle, σ(θ), or dσ/dΩ, with units of mb/sr
∆Ω = solid angle of detector (sr)
Total steradians in a sphere = 4π
∆A = area of detector face
∆Ω = 4π ∆A/(4πr 2 ) = ∆A/r 2
R detector
= N i
[σ(θ) ∆Ω] (nAt)/A = N i
[σ(θ) ∆Ω] nt