Characterization of a magnetic field sensor based on torque measuring [for fusion diagnostics application]

A sensor for low-frequency measurements of the magnetic field is presented in the paper. It is based on measurements of an electromagnetic torque. An output directly proportional to the unknown magnetic field is produced. This method has the main advantage of avoiding the drift present in the integration of signals from inductive sensors. The design and construction criteria, aiming at an uncertainty of a few milliteslas in field measuring, are described. The analysis of the sensor linearity is presented in the paper together with the test rig, able to guarantee reproducible conditions. The dynamic behavior of the torque-based sensor is considered. It is studied either on the basis of the coil and load cell characteristics or analyzing the response to an applied known electromagnetic torque.