Application of the escape factor method for determination of excited states densities in a low‐pressure argon radio‐frequency discharge

Reabsorption of the emitted light in the plasma volume has recently been used for density measurements of the lower level of optical transition by interpretation of emission spectra employing the escape factor concept. Following this idea, we apply this method to a radio‐frequency argon discharge. By revising the theoretical background, the impact of different assumptions on excited species spatial distributions is investigated. Comparing with 1s₅ and 1s₄ concentrations obtained with laser absorption spectroscopy, the range of applicability of those assumptions is analyzed at different discharge parameters. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)