Ultrafast Transient Experimental Facility (UTEF) is a 3rd generation light source, including a 500MeV full energy linear accelerator (Linac), a storage ring and beamlines, jointly constructed by Chongqing University and Shanghai Jiao Tong University. Before the installation of the Linac, we made an acceptance test of the electron gun injector. The electron gun provides a beam with 1ns of the pulse full width at half maximum (FWHM), then the sub-harmonic buncher (SHB) compresses the long pulse electron beam to less than the fundamental wavelength. An MTCA.4 based low level RF (LLRF) system drives the solid state amplifier (SSA), and stabilizes the amplitude and phase of the accelerating field of the SHB, meeting the requirements of the Linac.
Zhang et al. (Sun,) studied this question.