Abstract: The invention relates to an apparatus and to a process for producing bremsstrahlung. This apparatus comprises in a ferromagnetic member a circular cavity containing electrons rotated on a circular path under the action of a magnetic field induced by the ferromagnetic member and by means for inducing a magnetic field. The apparatus also comprises a circular target partly located outside the cavity and rotating in a plane perpendicular to that of the path of the electrons. The end of the target periodically traverses said path in order to interact periodically with the electrons on their path, so as to produce bremsstrahlung. Means are provided for varying the magnetic field in the cavity and are synchronized with the interaction period of the target on the electrons and are connected to the induction means.Application to all fields requiring the production bremsstrahlung.