he wavegui system of the HLS 800 MeV Linac

o upgrade Hefei Light Source (HLS) Linac, eight accelerating units have been constructed to realize full-energy injection of the storage ring. Each of the units consists of two 3-m accelerators driven by one klystron. The input cavity detuning method was developed to measure and correct the phase length of the RF power distribution waveguide system. The design of the waveguide network and the principles of the detuning method are presented in this paper. After correction, the phase error between the waveguide of the two accelerators was less than ?0.5?, and the maximum electron energy of Linac reached 805 MeV, which is very near the theoretical maximum value of 810 MeV. These results demonstrate that the calibration of the waveguide was successful.