A Faraday effect magnetic stripe scanner

摘要

We report on the realization of a Faraday magnetometer to characterize the magnetization of a magnetic foil during its production process at full speed of 3 m/s. The system is designed towards attaining a spatial resolution both in feeding direction and transverse to it of approximately 60 μm and is able to acquire in excess of 60.000 scan lines per second obtained from a line-scan camera with 128 pixels. We further report on the resolution of this system regarding the magnitude of the magnetization of the stripe and contrast this to the attainable noise figure determined by the optical properties of the used crystal, the illumination system and the camera.