What are mineral insulated thermocouples and how are they constructed?

Mineral insulated thermocouples are temperature sensors in which two different thermowires are embedded in a metal sheath. The wires are electrically insulated by compacted magnesium oxide and connected to each other at the measuring tip. Thanks to their robust, flexible design, mineral insulated thermocouples are bendable, vibration-resistant and suitable for high temperatures. The measuring principle of thermocouples is based on the Seebeck effect, in which a temperature-dependent thermoelectric voltage is generated at the junction of two different metals. This voltage is measured and converted into the corresponding temperature.