Report on the development of flux-gate magnetic sensors

Magnetic sensors of the " flux - gate " type have been studied at Consorzio RFX as a possible candidates for magnetic measurements inside HNB and MITICA vessel, in compliance with the specific requirements described in the ITER technical specification document [1] . A numerical model describing the internal behavior of these sensors, including the hysteresis of the ferromagnetic core , has been developed and used to evaluate the possibility of extending the measurement range of these sensors, which is very limited in the commercially available sensors . On the basis of the design criteria extracted from the numerical model, a flux - gate sensor prototype has then be built and tested, showing that the measurement range can be increased up to the level required for the ITER HNB application, with acceptable loss of accuracy.