• K. Koyama
  University of Tokyo, Tokyo
• A. Maekawa, H. Masuda, M. Uesaka
  The University of Tokyo, Nuclear Professional School, Ibaraki-ken
• Y. Oishi
  Central Research Institute of Electric Power Industry, Yokosuka-shi, Kanagawa

We are studying the artificial injection of initial electrons into the wakefield for producing stable electron bunch (the charge is 100 pC, the energy stability is better than a few per cent). The objective of our research is to produce 100-keV class monochromatic X-ray pulses for measuring concentrations of nuclear materials in a reprocessing plant. A K-edge densitometry using monochromatic hard x-ray beams is one of the effective technique to measure concentrations of nuclear materials in a reprocessing solutions. An inverse Compton scattering process between an IR-laser beam of 800 nm and high-energy electron bunch of above 80 MeV makes it possible to deliver tunable monochromatic x-rays near K-absorption edges of nuclear materials of 115-129 keV. In order to use in a reprocessing plant, the equipment for the K-edge densitometry must be smaller than a compact car. The only solution to realize the compact system is to use a laser wakefield accelerator instead of a radio frequency linac. An ultra-short ten-TW laser pulse focused on a supersonic jet makes it possible to accelerate electrons up to 100 MeV in a plasma length of 2.5 mm.

• A. Sagisaka, P.R. Bolton, S.V. Bulanov, H. Daido, T. Esirkepov, T. Hori, S. Kanazawa, H. Kiriyama, K. Kondo, S. Kondo, M. Mori, Y. Nakai, M. Nishiuchi, K. Ogura, H. Okada, S. Orimo, A.S. Pirozhkov, H. Sakaki, F. Sasao, H. Sasao, T. Shimomura, A. Sugiyama, H. Sugiyama, M. Tampo, M. Tanoue, D. Wakai, A. Yogo
  JAEA, Kyoto
• I.W. Choi, J. Lee
  APRI-GIST, Gwangju
• H. Nagatomo
  ILE Osaka, Suita
• K. Nemoto, Y. Oishi
  Central Research Institute of Electric Power Industry, Yokosuka-shi, Kanagawa

High-intensity laser and thin-foil interactions produce high-energy particles, hard x-ray, high-order harmonics, and terahertz radiation. A proton beam driven by a high-intensity laser has received attention as a compact ion source for medical applications. We have performed the high intensity laser-matter interaction experiments using a thin-foil target irradiated by Ti:sapphire laser (J-KAREN) at JAEA. In this laser system, the pulse duration is 40 fs (FWHM). The laser beam is focused by an off-axis parabolic mirror at the target. The estimated peak intensity is ~5x10¹⁹ W/cm². We have developed on-line real time monitors such as a time-of-flight proton spectrometer which is placed behind the target and interferometer for electron density profile measurement of preformed plasma. We observed the maximum proton energy of ~7 MeV.