  A beam monitor detector prototype based on doped silica fibres coupled to
optical fibres has been designed, constructed and tested, mainly for
accelerators used in medical applications. Scintillation light produced by Ce
and Sb doped silica fibres moving across the beam has been measured, giving
information on beam position, shape and intensity. Mostly based on commercial
components, the detector is easy to install, to operate and no electronic
components are located near the beam. Tests have been performed with a 2 MeV
proton pulsed beam at an average current of 0.8 {\mu}A. The response
characteristics of Sb doped silica fibres have been studied for the first time.
