On the inversion mechanism in the CW argon-ion laser

Temperatures and densities of atoms and electrons were obtained by spectroscopic methods in a gas discharge plasma used for CW ion-argon lasers. The measurements were carried out with capillaries 250-400 mm long with a bore diameter of 1.6-2.8 mm. The filling pressures were 0.2-0.7 torr and the discharge current densities 100-500 A/cm
²
. Electron temperatures were found from measured side-on widths of ArII lines using the Kagan-Perel theory. The electron densities were determined from the width of the H
β
line and from electro-conductivity. The ionization rate was evaluated through the Doppler shift of spectral lines as well as through half-widths of the ArII lines taken along the discharge. For this purpose, the Kagan-Perel theory was used also. Population rates of the
4s, 5s, 4p, 3d
, and
4d
ArII configurations of the ion ground state were calculated as well as radiation transition probabilities. With the aid of these data, population rates and densities were found for the doublet term system of configurations
4s
and
4p
. Population inversion was also evaluated. A comparison of the results of calculation with the experiment was carried out.