A dual detector includes a detection head having a platform and an inductive sensor that is mounted on the platform and includes a transmitter coil and a separate receiver coil. The transmitter coil and the receiver coil each form a loop, the loop of the transmitter coil at least partially overlapping the loop of the receiver coil so as to form a coupling region that is elongate in a first longitudinal direction defining a first axis, the arm extending on a plane that runs perpendicularly to the platform, and the first axis of the coupling region running transversely to the plane.