UNCD-Armoured Probes for Diagnostics in Hot and Hazardous Plasmas

Plasma probes are simple and inexpensive diagnostic tools which now are used even in hot and hazardous plasmas, where, however, especially the probe casings, often consisting of graphite, might suffer from sputtering, evaporation and chemical reactions between plasma particles and the probe material. An additional detrimental effect frequently detected is that the sputtered-off electrically conductive graphite re-deposits on the boron nitride material usually used for electrical isolation of the probe pins, leading to unwanted and possibly dangerous shunts to ground and/or to adjacent probes, or even short circuits.