Abstract: An apparatus for measuring a plasma parameter in a plasma processing reactor comprises a probe including a dielectric tube, a coaxial cable inserted in the dielectric tube, the coaxial cable having an open antenna tip, and a plurality of spacers disposed between the coaxial cable and the dielectric tube. The plurality of spacers define a plurality of ducts through which a cooling fluid is adapted to be circulated to control a temperature of the probe.

Abstract: An apparatus for measuring plasma density of a plasma processing reactor, comprises a probe having a dielectric tube with a coaxial cable inserted therein. The coaxial cable has an open antenna tip, distance constancy is kept between the antenna tip and the dielectric tube despite varying thermal conditions. The probe can be utilized to determine resonant plasma frequency near its tip location and the corresponding plasma density.