Two types of radio-frequency electron accelerators are described in this article. They operate in the frequency range of 100-200 MHz and are energized with triode or tetrode tubes instead of klystrons. They can provide more powerful electron beams than typical microwave linear accelerators. Keywords: ILU accelerators; Rhodotron accelerators; electron beam processing; X-ray processing. 213 Rev. Accl. Sci. Tech. 2011.04:213-218. Downloaded from www.worldscientific.com by NANYANG TECHNOLOGICAL UNIVERSITY on 08/24/15. For personal use only.