Electric discharge excitation of thallium in high‐pressure xenon

We report data obtained in pulsed 1.5–280‐MW/l electric discharges in thallium‐doped xenon gas at thallium densities of (1.5–26) ×10¹⁵ cm⁻³ and xenon densities of (1–4) ×10¹⁹ cm⁻³. Stable steady‐state discharges were obtained without the use of preionization or sustainers. Steady‐state E/N, J/N, and Tl and Xe excited‐state populations were determined for the positive column of the discharge. These measurements indicate an electron temperature of 0.45–0.65 eV, with the gas temperature remaining at ∼0.1 eV during the several‐microsecond discharges. The thallium states lower in energy than Tl(8S_1/2) generally show a higher excitation temperature than the states from Tl(8S_1/2) to the thallium ionization limit, particularly at the higher current densities. The homogeneity of a 9‐cm‐long transverse discharge and the effects of this discharge on a laser beam propagating through the thallium‐xenon medium were investigated. The implications of these results for a discharge‐pumped Tl‐Xe excimer laser are discussed.