M_gas 40[g/mol] "Molar mass: neutral gas (Ar)"
M_p 1[g/mol] "Molar mass: particles (H+)"
E_p 1[keV] "Energy: particles (H+)"
N0 1000 "Number of particles"
E1 2.16[eV] "Energy loss collision 1"
E2 13.6[eV] "Energy loss collision 2"
E3 15.6[eV] "Energy loss collision 3"