Atomic and nuclear properties of materials:
Argon gas (Ar)
QuantityValueUnits ValueUnits
Atomic number 18     
Atomic mass 39.948(1) g mole-1   
Specific gravity (20° C, 1 atm) 1.66E-03 g cm-3   
Mean excitation energy 188.0 eV   
Minimum ionization 1.519 MeV g-1cm2 2.525E-03 MeV cm-1
Nuclear collision length 75.7 g cm-2 4.557E+04 cm
Nuclear interaction length 119.7 g cm-2 7.204E+04 cm
Pion collision length 101.3 g cm-2 6.097E+04 cm
Pion interaction length 149.0 g cm-2 8.964E+04 cm
Radiation length 19.55 g cm-2 1.176E+04 cm
Critical energy 38.03 MeV (for e-) 37.06 MeV (for e+)
Molière radius 10.90 g cm-2 6559. cm
Plasma energy 0.79 eV   
Muon critical energy 572. GeV   
Melting point 83.81 K -189.3 C
Boiling point @ 1 atm 87.26 K -185.9 C
Index of refraction (@ STP, Na D) 281. (n-1)x106     
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