X‐ray preionization of self‐sustained, transverse excitation CO2 laser discharges

TLDR: In this article, a flash x-ray source was used to preionize high-pressure CO2 laser mixtures so as to obtain uniform glow discharges, and the resulting discharges were shown to tolerate oxygen (up to 2.6%) better.

Abstract: X rays with a mean energy of ∼50 keV produced by a flash x‐ray source have been used to preionize high‐pressure CO2 laser mixtures so as to obtain uniform glow discharges. The x‐ray exposure measured in the active volume was 1–2 mR/pulse with a pulse duration of 100 nsec (FWHM) which permitted specific energy inputs of up to 300 J/l atm. Glow discharges were obtained for a variety of pressures and gas mixtures including some which were helium‐free or in which helium was replaced by argon. Further, a realistic comparison of UV and x‐ray schemes was made under sealed‐off conditions. X‐ray preionization appears to be advantageous and the resulting discharges are shown to tolerate oxygen (up to 2.6%) better. Additives such as xenon or organic compounds were not necessary for obtaining uniform glow discharges.