• S. Kashiwagi, K. Furuhashi, G. Isoyama, R. Kato, M. Morio, N. Sugimoto, Y. Terasawa
  ISIR, Osaka
• H. Hayano, H. Sugiyama, J. Urakawa, K. Watanabe
  KEK, Ibaraki
• D. Kubo, M. Kuriki, C. Shonaka
  HU/AdSM, Higashi-Hiroshima

We have begun the development of L-band photocathode RF gun for the 40 MeV L-band linac at ISIR, Osaka University to advance studies such as FEL and pulse radiolysis experiments in the future with the high-intensity and low emittance electron beam. Before it installs the RF gun into Osaka University, we plan to develop and commission the L-band RF electron gun for the Superconducting RF Test Facility (STF) at High Energy Accelerator Research Organization (KEK). While waiting for delivery of an RF cavity and an input coupler from the Fermi National Accelerator Laboratory, we have fabricated a test RF gun cavity and a coaxial input coupler made from Aluminium and investigated the rf properties of them. The resonant frequency and field balance of the real RF gun cavity have been adjusted using a tuning apparatus at KEK-STF. Some results of the development are reported, including the tuning of RF characteristics of the cavity, design of an input coupler and solenoid magnet for emittance compensation, and computer simulation for characteristics of the accelerated electron beam.

• R. Kato, K. Furuhashi, G. Isoyama, S. Kashiwagi, M. Morio, Y. Terasawa
  ISIR, Osaka

The performance of the free-electron laser based on self-amplified spontaneous emission strongly depends on time-sliced characteristics of the electron beam, such as longitudinal charge distribution, slice energy spread and transverse slice emittance. We have developed a longitudinal phase space measurement system consisted of a Cherenkov radiator, a bending magnet and a streak camera and reconstructed the longitudinal phase-space image of the high brightness electron beam accelerated by the L-band electron linac at ISIR, Osaka University [1]. Using a quadruple magnet instead of the bending magnet, this technique can be applied to measure the transverse slice emittance of the electron beam. A few slice emittance measurement techniques were already studied and turned into actual utilization; however our idea provides a simpler and more convenient technique. This paper describes a design conceptual of the slice emittance measurement system.

[1] R. Kato et al., “Study on Longitudinal Phase-space of High-brightness Electron Beams at ISIR, Osaka University”, Proceedings of EPAC’08, Genoa, Italy, June 23 - 27, 2008, pp.1161-1163.