• T. Kamitani, M. Akemoto, D.A. Arakawa, A. Enomoto, S. Fukuda, K. Furukawa, T. Higo, H. Honma, K. Hosoyama, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, H. Katagiri, M. Kikuchi, Y. Kojima, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Mimashi, T. Miura, H. Nakajima, K. Nakanishi, K. Nakao, Y. Ogawa, S. Ohsawa, T. Sanami, M. Satoh, T. Shidara, A. Shirakawa, T. Sugimura, T. Suwada, T. Takenaka, M. Tawada, Y. Yano, K. Yokoyama, M. Yoshida
  KEK, Ibaraki

The KEKB-factory will be upgraded for 40 times higher lumnosity (SuperKEKB). The injector linac is required to increase the beam intensities (e-:1nC -> 5nC, e-:1nC -> 4nC) and reduce the emittances (e-:300 -> 20 um, e+: 2100 -> 10 um ) for the SuperKEKB. A photo-cathode RF gun will be introduced to generate the high-intensity and low-emittance electron beams. A positron damping ring will be constructed to reduce the emittance. A new matching device (a flux concentrator or a superconducing magnet) and an L-band capture section will be introduced to increase the positron intensity. Beam line layout down to the damping ring will be rearranged to have sufficient beam acceptance considering the positron emitttance. This paper describes details of the upgrade scheme of the injector linac.

• T. Suwada, M. Satoh
  KEK, Ibaraki

A new laser-based alignment system is under development in order to precisely align accelerator components along an ideal straight line at the KEKB injector linac towards the next generation of B-factories. A new laser optics generating so-called Airy beam has been developed for the laser-based alignment system. The laser-beam propagation characteristics both in vacuum and at atmospheric pressure have been systematically investigated at a 82-m-long straight section of the injector linac. The results in the measured propagation characteristics are in good agreement with those analyzed on the basis of theoretical analysis in Gaussian laser propagation. In this report the experimental study is described in detail along with the basic design and recent development of the new laser-based alignment system.

• M. Satoh, T. Suwada
  KEK, Ibaraki

A new laser-based alignment system is under development in order to precisely align accelerator components along an ideal straight line at the KEKB injector linac. The new alignment system is strongly required in order to stably accelerate high-brightness electron and positron beams with high bunch charges and also to keep the beam stability with higher quality towards the next generation of B-factories. The new laser-based alignment system consists of the LD mounted on auto stage, vacuum duct, photo diode (PD) and PD detector. To eliminate the laser beam size dependent response of PD, the collimated laser beam propagation along the linac (around 500-m-long) is strongly required. In this paper, we will report the design of collimated laser beam optics for the KEKB injector linac alignment system in detail.