Atomic and nuclear properties of liquid argon (Ar)
QuantityValueUnits ValueUnits
Atomic number 18     
Atomic mass 39.948(1) g mole-1   
Specific gravity 1.396 g cm-3   
Mean excitation energy 188.0 eV   
Minimum ionization 1.508 MeV g-1cm2 2.105 MeV cm-1
Nuclear collision length 75.7 g cm-2 54.25 cm
Nuclear interaction length 119.7 g cm-2 85.77 cm
Pion collision length 101.3 g cm-2 72.58 cm
Pion interaction length 149.0 g cm-2 106.7 cm
Radiation length 19.55 g cm-2 14.00 cm
Critical energy 32.84 MeV (for e-) 31.91 MeV (for e+)
Molière radius 12.62 g cm-2 9.043 cm
Plasma energy ωp 22.85 eV   
Muon critical energy 485. GeV   
Melting point 83.79 K -189.4 C
Boiling point @ 1 atm 87.30 K -185.9 C
Index of refraction (Na D) 1.233     
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
Table of isotopes Warning: may not be current
x ray mass attenuation coefficients