Thermal induced electromotive force measurements on twisted pair mineral insulated cables

•Thermal Induced Electromotive Force measurements on mineral insulated cables.•Optimization of test procedure.•Thermal simulation of mineral insulated cables. The ITER Diagnostics components are located all over on the inner and outer shell of the ITER vacuum vessel, in the ports, on the Divertor Cassettes and in the Cryostat as well. Sensors require electrical transmission lines to transmit both the diagnostic and the control signals across the vacuum boundaries. To transmit the signals, Mineral Insulated (MI) cables are used. During the last 2 years in the frames of an F4E contract, the Tokamak Services for Diagnostics (TSD) group has performed several experiments on MI cables, in close collaboration with F4E and IO team members. This paper outlines one of these experiments to measure the thermal gradient induced voltage in the cable cores. This is needed to evaluate the electrical noise levels due to the thermal gradients in order to know if the noise has significant effect on the signal quality of some sensitive diagnostics. The subjects of the tests are a couple of Twisted Twin Mineral Insulated Cables (MICs) as this type of cables are used by the magnetics in the ITER machine.