Author: Satoh, D.
Paper Title Page
MOPFI023 Development of Better Quantum Efficiency and Long Lifetime Iridium Cerium Photocathode for High Charge electron RF Gun 327
 
  • D. Satoh
    TIT, Tokyo, Japan
  • N. Hayashizaki
    RLNR, Tokyo, Japan
  • M. Yoshida
    KEK, Ibaraki, Japan
 
  We developed an Ir5Ce photocathode as a high charge electron source for SuperKEKB electron linac. The required electron beam parameters are 5 nC and 10 mm•mrad from the electron gun of the SuperKEKB electron linac. We plan to generate this electron beam using a laser-driven RF gun installed with a photocathode that has a long lifetime and a high-power laser system through more than a year without replacement. Therefore, we focused on the Ir5Ce compound as a new photocathode which has a high melting point (> 2100 K) and a low work function (2.57 eV). The results of measurements showed that the quantum efficiency of Ir5Ce photocathode was 1.0×10-4 treated by the laser cleaning using the 4nd harmonic of Nd:YAG laser or the heater treatment. Furthermore, its photoemission properties could be maintained for a long term even if its photocathode was in the low vacuum conditions ( ~10-6 Pa) since the Ir5Ce compound is far less contaminated than other photocathodes. Finally, We have succeed to generate electron beams of 4.4 nC by the Ir5Ce photocathode installed at the 3-2 sector DAW type RF gun and accelerate it through a linac end in KEK electron linac.  
 
TUPME010 High-intensity and Low-emittance Upgrade of 7-GeV Injector Linac towards SuperKEKB 1583
 
  • K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
    KEK, Ibaraki, Japan
  • D. Satoh
    TIT, Tokyo, Japan
 
  After a decade of successful operation at KEKB a new electron/positron collider, SuperKEKB, is being constructed to commission within FY2014. It aims at a luminosity of 8 x 1035 /s.cm2, 40-times higher than that of KEKB, in order to study the flavor physics of elementary particles further, by mainly squeezing the beams at the collision point. The injector linac should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron by newly installing a RF-gun, a flux concentrator, and a damping ring with careful emittance and energy management. It also have to perform simultaneous top-up injections into four storage rings by pulse-to-pulse beam modulations not to interfare between three facilities of SuperKEKB, Photon Factory and PF-AR. This paper describes the injector design decisions and present status of the construction.