Atomic and nuclear properties of skin (ICRP)
QuantityValueUnits ValueUnits
<Z/A> 0.54932     
Specific gravity 1.100 g cm-3   
Mean excitation energy 72.7 eV   
Minimum ionization 1.969 MeV g-1cm2 2.166 MeV cm-1
Nuclear collision length 58.4 g cm-2 53.05 cm
Nuclear interaction length 83.1 g cm-2 75.59 cm
Pion collision length 85.8 g cm-2 78.04 cm
Pion interaction length 115.1 g cm-2 104.6 cm
Radiation length 37.67 g cm-2 34.25 cm
Critical energy 81.18 MeV (for e-) 79.02 MeV (for e+)
Molière radius 9.84 g cm-2 8.946 cm
Plasma energy ℏωp 22.40 eV   
Muon critical energy 1059. GeV   
Composition:
Elem ZAtomic frac* Mass frac
H
1
1.00
0.100588
C
6
0.19
0.228250
N
7
0.03
0.046420
O
8
0.39
0.619002
Na
 11
0.00
0.000070
Mg
 12
0.00
0.000060
P
15
0.00
0.000330
S
16
0.00
0.001590
Cl
 17
0.00
0.002670
K
19
0.00
0.000850
Ca
 20
0.00
0.000150
Fe
 26
0.00
0.000010
Zn
 30
0.00
0.000010
* calculated from mass fraction data

For muons, dE/dx = a(E) + b(E) E. Tables of b(E): PDF TEXT
Table of muon dE/dx and Range: PDF TEXT
Explanation of some entries