Atomic and nuclear properties of materials:
Tantalum (Ta)

Quantity	Value	Units	Value	Units
Atomic number	73
Atomic mass	180.94788(2)	g mole-1
Density	16.7	g cm-3
Mean excitation energy	718.0	eV
Minimum ionization	1.149	MeV g-1cm2	19.14	MeV cm-1
Nuclear collision length	109.9	g cm-2	6.599	cm
Nuclear interaction length	191.0	g cm-2	11.47	cm
Pion collision length	133.4	g cm-2	8.011	cm
Pion interaction length	217.7	g cm-2	13.07	cm
Radiation length	6.82	g cm-2	0.4094	cm
Critical energy	8.09	MeV (for e-)	7.79	MeV (for e+)
Molière radius	17.88	g cm-2	1.073	cm
Plasma energy	74.69	eV
Muon critical energy	152.	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 Warning: may not be current
x ray mass attenuation coefficients