• M. Uesaka, Y. Muroya, T. Ueda
  The University of Tokyo, Nuclear Professional School, Ibaraki-ken
• K. Kanbe, K. Miyoshi
  University of Tokyo, Tokyo

We are commissioning the cathode, Na2KSb at the wavelength of 266, 400 nm with thermo-mechanically modified structure and improved vacuum system (2·10^-08 Pa). We could improve RF reflection waveform and obtain the maximum energy of 22 MeV. We estimate the electrical field of 50 MV at the cathode. So far, we have obtained the quantum efficiencies of 1.1, 0.01% and the maximal charges of 4.6, 1 nC for 266, 400 nm. We are observing and checking carefully individual difference of QE of the cathodes for 266, 400 nm, and we have obtained 22 MeV energy. This new RF photocathode RF gun system has been already used for subpicosecond time-resolved radiation chemistry.