Atomic and nuclear properties of materials:
Tissue-equivalent gas (Propane based)

Quantity	Value	Units	Value	Units
<Z/A>	0.55027
Specific gravity (20° C, 1 atm)	1.83E-03	g cm-3
Minimum ionization	2.068	MeV g-1cm2	3.778E-03	MeV cm-1
Nuclear collision length	57.6	g cm-2	3.153E+04	cm
Nuclear interaction length	81.6	g cm-2	4.470E+04	cm
Pion collision length	85.1	g cm-2	4.660E+04	cm
Pion interaction length	113.6	g cm-2	6.220E+04	cm
Radiation length	40.91	g cm-2	2.240E+04	cm
Critical energy	109.50	MeV (for e-)	107.13	MeV (for e+)
Molière radius	7.92	g cm-2	4338.	cm
Plasma energy	0.91	eV
Muon critical energy	1335.	GeV

Composition:

Elem	Z	Atomic frac*	Mass frac*
H	1	1.00	0.102672
C	6	0.47	0.568940
N	7	0.02	0.035022
O	8	0.18	0.293366
* calculated from mass fraction data.

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