Electron accelerator of the re-circulating type, having a resonant coaxial cavity presenting an outer cylindrical conductor of axis A and a coaxial inner cylindrical conductor, an electron gun for injecting electrons into the cavity following a radial direction and into a median plane of the cavity, an RF system capable of accelerating the injected electrons following a trajectory into the median plane which has the shape of a flower centered on the axis A, deflecting magnets disposed into the median plane externally to the cavity for redirecting electrons back towards the axis A. The RF system includes final power amplifiers, each amplifier being directly coupled to the cavity through its own individual inductive loop and each two of these loops being physically spaced apart from each other by an angle alpha, such that alpha is not an integer multiple of 90 degrees.