Atomic and nuclear properties of silica aerogel for rho = 0.2 (0.03 H₂O, 0.97 SiO₂)

Quantity	Value	Units	Value	Units
<Z/A>	0.50093
Specific gravity	0.2000	g cm-3
Mean excitation energy	139.2	eV
Minimum ionization	1.740	MeV g-1cm2	0.3480	MeV cm-1
Nuclear collision length	65.0	g cm-2	324.9	cm
Nuclear interaction length	97.3	g cm-2	486.7	cm
Pion collision length	91.7	g cm-2	458.6	cm
Pion interaction length	128.4	g cm-2	641.9	cm
Radiation length	27.25	g cm-2	136.2	cm
Critical energy	56.07	MeV (for e-)	54.63	MeV (for e+)
Molière radius	10.31	g cm-2	51.53	cm
Plasma energy ℏωp	9.12	eV
Muon critical energy	762.	GeV

Composition:

Elem	Z	Atomic frac*	Mass frac
O	8	2.00	0.543192
Si	14	1.00	0.453451
H	1	2.00	0.003357
* 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
Note: See A. R. Buzykaev et al, NIM A433 396 (1999)