• W.H. Hwang, K.M. Ha, K.R. Kim, S.H. Kim, S.H. Kim, S.S. Park, Y.G. Son
  PAL, Pohang, Kyungbuk
• M. Yoon
  POSTECH, Pohang, Kyungbuk

Pohang Accelerator Laboratory, PAL, has been proposing a 0.1 nm SASE FEL. This machine will be designed with an S-band rf linear accelerator to produce a 10.053 GeV electron beam. The output power of klystron is 80 MW at the pulse width of 4 μs and the repetition rate of 30 Hz. The beam energy spread is 0.037%(rms), and rf phase stabiltity is 0.1 degrees(rms). The SASE FEL needs the modulator stability of 0.1%. We developed the modulator DeQing system to use the existing modulator systems that are “line type modulator system”. And we also are considering an inverter power supply to meet the required specification of the FEL machine. We are developing the phase amplitude detection system(PAD) and phase amplitude control(PAC) system to obtain the required rf stability. This paper describes the rf system for PAL XFEL(PxFEL).

• H.-S. Kang, Y.-G. Jung, C. Kim, H.-G. Kim, K.R. Kim, W.W. Lee, B.R. Park, J. Park, Y.J. Park, Y.G. Son, H.S. Suh, I.H. Yu
  PAL, Pohang, Kyungbuk
• D.E. Kim, C.M. Yim
  POSTECH, Pohang, Kyungbuk

A femto-second THz radiation (fs-THz) facility is under commissioning at the Pohang Accelerator Laboratory (PAL), which uses a 60-MeV electron linac that consists of an S-band photocathode RF gun with 1.6 cell cavity, two S-band accelerating structures, and two chicane-type bunch compressors. The linac is designed to generate THz pulse with energy up to 10 μJ by transition radiation from a metal target hit by sub-picosecond electron beam. The linac takes advantage of the advanced technologies such as an inverter-type klystron modulator with stability below 100 ppm and a high precision synchronization timing system with a laser oscillator. The THz radiation energy measured with a Golay cell is 0.5 μJ/pulse from the electron beam with charge of 0.1 nC. We will present the properties of THz radiation as well as the electron beam parameters.