Experimental investigation of a low-pressure N/sub 2/-O/sub 2/ microwave discharge

Summary form only given. Microwave N/sub 2/-O/sub 2/ discharges driven by traveling surface waves attract attention as sources of active species, in particular for cold plasma sterilization of surgical material and other medical devices. The objective of this study is to investigate the concentration of various active species, such as O and N atoms, N/sub 2//sup +/ ions, and N/sub 2/(A/sup 3//spl Sigma//sub u//sup +/) and NO(A/sup 2//spl Sigma//sub u//sup +/) molecules, as a function of the spatial position and the mixture composition in an azimuthally symmetric surface wave driven discharge operating at /spl omega//2/spl pi/=2.45 GHz. The plasma column is created in N/sub 2/-xO/sub 2/ mixtures (x/spl les/25%) at the pressure p=5 Torr, in a quartz glass tube with inner radius a=0.25 cm, with flow rates in the range Q=300-1000 sccm and microwave power between 100 and 150 watts. Emission spectroscopy is used to measure the N/sub 2/(1/sup +/,2/sup +/,1/sup -/) and NO(/spl gamma/, /spl beta/) band intensities in the discharge and in early post-discharge.