• T.-Y. Lee, M.S. Chae, J. Choi, H.-S. Kang, M. Kim
  PAL, Pohang, Kyungbuk
• I.S. Ko
  POSTECH, Pohang, Kyungbuk

This paper discusses feasibility of a compact XFEL in the future. It gives theoretical argument how a compact XFEL can be possible. For that purpose, a method of energy scaling is developed. It is shown that an extremely low emittance electron gun is an essential element for the realization of a compact XFEL.

• 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.