Atomic and nuclear properties of materials:
Protactinium (Pa)
QuantityValueUnits ValueUnits
Atomic number 91     
Atomic mass [231.03588(2)] g mole-1   
Density 15.4 g cm-3   
Mean excitation energy 878.0 eV   
Minimum ionization 1.107 MeV g-1cm2 17.02 MeV cm-1
Nuclear collision length 117.6 g cm-2 7.651 cm
Nuclear interaction length 207.0 g cm-2 13.47 cm
Pion collision length 140.6 g cm-2 9.149 cm
Pion interaction length 233.3 g cm-2 15.18 cm
Radiation length 5.93 g cm-2 0.3861 cm
Critical energy 6.77 MeV (for e-) 6.52 MeV (for e+)
Molière radius 18.59 g cm-2 1.209 cm
Plasma energy 70.90 eV   
Muon critical energy 130. GeV   
Melting point 1845. K 1572. C
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
Note: There is a well-defined terrestrial aboundance for protactinium even though it is radioactive.
Table of isotopes Warning: may not be current
x ray mass attenuation coefficients