Producing high quality LTCC sensors for ITER in-vessel magnetic diagnostics

Abstract

Inductive magnetic sensors inside the vacuum vessel of ITER tokamak are crucial for plasma operation, plasma control and physics studies. This set of sensors was designed based on the LTCC (Low Temperature Co-Fired Ceramic) technology in order to survive the hostile environment inside ITER vacuum vessel with restricted space, high vacuum, high heat load, and high radiation level. Some features were also integrated into the sensor design to address specific service loads, for instance, accidental superheated steam intrusion. As per ITERs diagnostics design, in total 300 LTCC magnetic sensors have been successfully produced according to the manufacture design and following the specifically developed fabrication process. Extensive quality control program and rigorous factory acceptance tests had been implemented throughout mass production (final 300 sensors). These practices ensured that the sensors were produced to the desired quality and with high reliability.