• J.-S. Oh, S. D. Jang, I.S. Ko, S. J. Kwon, W. Namkung, Y. G. Son, J.-H. Suh
  PAL, Pohang, Kyungbuk

Funding: Supported by the POSCO and the MOST, Korea

The PAL (Pohang Accelerator Laboratory) is persuading to construct a SASE-XFEL facility (PAL XFEL) that supplies coherent X-rays. The bright and stable electron beam is essential for the PAL XEL. The electron beams has to have an emittance of 1.2 mm-mrad, a peak current of 3.5 kA, and a low energy spread of 0.5 MeV. In order to provide reasonably stable SASE output, the RF stability of 0.02% rms is required for both RF phase and amplitude. This is a technologically challenging issue for PAL XFEL. An inverter technology is to be applied to charge the PFN of a new modulator. Therefore, a new inverter system should provide very stable charging performances. This paper presents the development of an ultra stable klystron-modulator with an inverter power supply.

• J.Y. Huang, Y.S. Bae, M.-H. Chun, Y.J. Han, S.-H. Jeong, H.-S. Kang, D.T. Kim, S.H. Kim, S.-C. Kim, I.S. Ko, H.J. Park, I.-S. Park, S.J. Park, Y.J. Park, S.Y. Rah, J.-H. Suh
  PAL, Pohang, Kyungbuk
• J.H. Hong, C. Kim
  POSTECH, Pohang, Kyungbuk

Funding: Work supported by Ministry of Science and Technology (MOST)

Beam diagnostics for PAL-XFEL physics calls for precision of femto-second in time structure and sub-micrometer in beam position measurement(BPM). Existing instruments can be used for standard diagnostics such as single bunch charge measurement, wire scanner or optical transition radiator for beam size measurement. Instead, major R&D efforts should be focused on the measurement of femto-second bunch structure using electro-optic crystal, coherent radiation and transverse deflecting cavity. Nanometer BPM technique being developed in collaboration with linear collider group will also be utilized for sub-micrometer BPM. Overall plan and the ongoing R&D activities will be presented.