Space resolved density measurements of argon and helium metastable atoms in radio-frequency generated He-Ar micro-plasmasB. Niermann, M. Böke, N. Sadeghi and J. WinterEur. Phys. J. D, 60 3 (2010) 489-495DOI: https://doi.org/10.1140/epjd/e2010-00166-8