Atomic and nuclear properties of materials:
Ruthenium (Ru)

Quantity	Value	Units	Value	Units
Atomic number	44
Atomic mass	101.07(2)	g mole-1
Specific gravity	12.4	g cm-3
Minimum ionization	1.307	MeV g-1cm2	16.22	MeV cm-1
Nuclear collision length	94.3	g cm-2	7.596	cm
Nuclear interaction length	158.4	g cm-2	12.76	cm
Radiation length	9.48	g cm-2	0.7641	cm
Critical energy	13.12	MeV (for e-)	12.68	MeV (for e+)
Molière radius	15.32	g cm-2	1.235	cm
Plasma energy	66.98	eV
Muon critical energy	225.	GeV

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
Explanation of some entries
Table of isotopes
x ray mass attenuation coefficients