Atomic and nuclear properties of polonium (Po)

Quantity	Value	Units	Value	Units
Atomic number	84
Atomic mass	[208.98243(2)]	g mol-1
Density	9.320	g cm-3
Mean excitation energy	830.0	eV
Minimum ionization	1.141	MeV g-1cm2	10.63	MeV cm-1
Nuclear interaction length	200.2	g cm-2	21.48	cm
Nuclear collision length	114.3	g cm-2	12.27	cm
Pion interaction length	226.4	g cm-2	24.29	cm
Pion collision length	137.6	g cm-2	14.76	cm
Radiation length	6.16	g cm-2	0.6611	cm
Critical energy	7.33	MeV (for e-)	7.06	MeV (for e+)
Muon critical energy	140.	GeV
Molière radius	17.83	g cm-2	1.913	cm
Plasma energy ℏωp	55.77	eV

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: Since there are no stable isotopes, [atomic mass] is that of the longest-lived isotope known as of Jun 2017.
Table of isotopes via WIKIPEDIA
x ray mass attenuation coefficients from NIST