Atomic and nuclear properties of brain (ICRP)
QuantityValueUnits ValueUnits
<Z/A> 0.55423     
Specific gravity 1.030 g cm-3   
Mean excitation energy 73.3 eV   
Minimum ionization 1.990 MeV g-1cm2 2.050 MeV cm-1
Nuclear collision length 58.4 g cm-2 56.69 cm
Nuclear interaction length 83.1 g cm-2 80.68 cm
Pion collision length 85.9 g cm-2 83.39 cm
Pion interaction length 115.0 g cm-2 111.7 cm
Radiation length 36.72 g cm-2 35.65 cm
Critical energy 79.96 MeV (for e-) 77.84 MeV (for e+)
Molière radius 9.74 g cm-2 9.455 cm
Plasma energy ℏωp 21.77 eV   
Muon critical energy 1046. GeV   
Composition:
Elem ZAtomic frac* Mass frac
H
1
1.00
0.110667
C
6
0.10
0.125420
N
7
0.01
0.013280
O
8
0.42
0.737723
Na
 11
0.00
0.001840
Mg
 12
0.00
0.000150
P
15
0.00
0.003540
S
16
0.00
0.001770
Cl
 17
0.00
0.002360
K
19
0.00
0.003100
Ca
 20
0.00
0.000090
Fe
 26
0.00
0.000050
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