Atomic and nuclear properties of radium (Ra)
QuantityValueUnits ValueUnits
Atomic number 88     
Atomic mass [226.02541(2)] g mole-1   
Specific gravity 5.000 g cm-3   
Mean excitation energy 826.0 eV   
Minimum ionization 1.111 MeV g-1cm2 5.555 MeV cm-1
Nuclear collision length 116.9 g cm-2 23.38 cm
Nuclear interaction length 205.5 g cm-2 41.09 cm
Pion collision length 139.9 g cm-2 27.99 cm
Pion interaction length 231.8 g cm-2 46.37 cm
Radiation length 6.15 g cm-2 1.230 cm
Critical energy 7.19 MeV (for e-) 6.94 MeV (for e+)
Molière radius 18.12 g cm-2 3.625 cm
Plasma energy ωp 40.21 eV   
Muon critical energy 137. GeV   
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