Electromagnetic acoustic transducer and method therefor

Abstract

An electromagnetic acoustic transducer, EMAT, assembly 600 comprises: an EMAT probe 210 comprising: a coil 262 to produce eddy currents in an object under inspection and a permanent magnet connected to the coil; and an EMAT probe position mechanism comprising; at least one actuator 232 coupled to the EMAT probe and arranged to locate the probe onto or adjacent the object; at least one movable device (wheels 620) coupled to the at least one actuator and arranged to move the EMAT probe around the object; and wherein the at least one actuator and the movable device in combination, are arranged to control: a magnetic field strength between the permanent magnet and the object under inspection, and a variable frictional force that is exerted on to the EMAT probe as the EMAT probe is guided over a surface of the object under inspection. A lift off sensor may be included. Figure 6