CERN Program Library Long Writeup W5013 - CERNLIB ...

where
N
Z(Z i )
A(A i )
ρ
σ
Avogadro’s number
atomic number (of i th component) of the medium
atomic mass (of i th component) of the medium
density
cross-section
n i proportion by number of the i th element in the material (n i = Wp i /A i
where p i is the corresponding proportion by weight and W is the molecular
weight).
The binding energy of the inner shells has been parameterised as:
E i (Z) =Z 2 (A i + B i Z + C i Z 2 + D i Z 3 ) MeV (7)
where, i = K, L I ,L II and the constants A i ,B i ,C i and D i are tabulated below.
A B C D
K 0.66644·10 −5 0.22077·10 −6 -0.32552·10 −8 0.18199·10 −10
L I -0.29179·10 −6 0.87983·10 −7 -0.12589·10 −8 0.69602·10 −11
L II -0.68606·10 −6 0.10078·10 −6 -0.14496·10 −8 0.78809·10 −11
The photoelectric effect total cross-section has been parameterised as:
p 1 /Z + p 2 X + p 3 + p 4 Z + p 5 /X + p 6 Z
⎧⎪ 2
+ p 7 Z/X + p 8 /X 2 + p 9 Z 3 if E>E k (Z)
⎨
σ(Z, E) =Z α X β + p 10 Z 2 /X + p 11 Z/X 2 + p 12 /X 3 (8)
p 13 /Z + p 14 X + p 15 if E LI