Cooling for capacitance probe center conductor

A capacitance probe for measuring clearances within a gas turbine engine, comprising:

• a center conductor having a face that is exposed to a gas-path of the gas turbine engine;
• a connection line;
• connection circuitry for interconnecting the center conductor with the connection line;
• a probe housing surrounding the center conductor, the connection line and the connection circuitry, the probe housing defining an opening for exposing the face of the center conductor to the gas-path of the gas turbine engine;
• wherein the center conductor and the probe housing define at least one horizontal channel that runs substantially parallel to the face of the face of the center conductor;
• wherein the probe housing further defines at least one first vertical channel interconnecting a cool air source to provide cooling air at a top of the probe housing to the at least one horizontal channel and defines at least one second vertical channel interconnecting the at least one horizontal channel to the gas-path;
• and
• wherein the at least one first vertical channel, the at least one horizontal channel and the at least one second vertical channel enables the cooling air to flow from the cool air source to the gas-path through the horizontal channel to cool the face of the center conductor.