The research and development of X-band acceleration has been conducted at KEK since 1989. The activity proceeded as the KEK’s main task force until the ITRP in 2004, aiming at the linear collider. Even after the ITRP chose the superconducting technology, KEK has continued the research of normal conducting X-band technology as one of the basic researches for high gradient acceleration at high frequency. In this report, some relevant achievements were reviewed such as the PPM klystron and the HOM-suppressed accelerating structure operated at 100 MV/m. Then, we discuss how we proceed this research in near future by taking into account the status of the linear collider research in the world.

A terminal ion injector using an all permanent magnet type electron cyclotron resonance (ECR) ion source has been constructed in the high voltage terminal of the vertical and folded type 20UR Pelletron tandem accelerator at Japan Atomic Energy Agency at Tokai. The new in-terminal injector made it possible to accelerate highly charged heavy ions which have not been obtained from the tandem accelerator. Beam energy and beam intensity have been remarkably increased and the noble gas ion beams have become available.

A new luminosity record of 21.08×10³³ cm^－2s^－1, which is the world record at present, was achieved at KEKB in the spring run of 2009. The previous record was 17.60×10³³cm^－2s^－1 achieved in November 2006. This significant improvement in the luminosity was brought mainly by the newly installed skew-sextupole magnets, which are believed to correct the chromaticity of x-y coupling at IP. In addition, the increase of the HER beam current also contributed to the luminosity improvement. This beam current increase became possible by solving the physical aperture problem around the crab cavities.

A successful simultaneous-injection with pulse-to-pulse mode-switch to the PF, KEKB–HER, and KEKB–LER rings from KEK Linac has greatly contributed to their upgraded performance. Detailed description of the system is presented.

My wandering about accelerator started from a van de Graaff accelerator on the Nakanoshima campus of Osaka University. The accelerator was originally designed by Prof. K. Husimi before the World-War II, and completed by Prof. K. Sugimoto, under the severe financial difficulties after the war. It was almost totally handmade, and consequently we were very well trained through various experiences fighting with difficulties. After finishing thesis work, I moved to Berkeley and enjoyed heavy-ion experiments at the world best heavy-ion accelerator, HILAC. The heavy-ion accelerator revealed new facets of nuclei through studies of high-spin states and phenomena.

A workshop was held in Perugia, Italy, from June 16th to the 19th on the design of a Super B factory, which is proposed to be built in Italy. This machine, called “SuperB,” would re-use many components of the PEP-II accelerator, while the detector would re-use components from the Babar detector. The design luminosity of the machine, however, would be much higher than that of PEP-II: 10³⁶ cm^－2s^－1 at the Y(4s) resonance. In addition, the machine is also planned to be run as a τ-charm factory with a luminosity of 10³⁵cm^－2s^－1 at a ∼4 GeV center-of-mass energy. The machine design also features polarized electrons. The challenges presented by these requirements and the evolving design of the accelerator part of the project (including siting issues) are discussed.