| abstract |
A micro plasma sensor system having a glow discharge gap. A fluid (17) to be sensed is brought into the vicinity of the discharge (18) at the gap. Emission light from the discharge is coupled to an optical spectrum analyzer (22, 23, 26, 47) for determining properties of the fluid. Window cleanliness and electrode electrical isolation may be maintened by the discharge. The optical analyzer may have individual bandpass filters (22) for two or more optical channels to optical detectors, a Fabry-Perot filter (26) in front of a set of optical detectors (41), or a grating or prism (48) which disperses emission light at various angles according to wavelength to an array of light detectors (49). The optical detectors (23, 41, 49) may output electrical signals to be processed. |