ATF-II is an extension of the ATF beamline, shown in gray structure. ATF-II will establish the beam position monitoring and control at the nanometer level.

The Accelerator Test Facility (ATF) at KEK, which has been in operation since 1994, consists of a 1.3GeV electron linac driven by a multi-bunch capable electron gun, a 1.3 GeV damping ring and a beam extraction line. It has been serving as a unique test facility
for establishing the feasibility of producing and controlling the ultra-low emittance beam that is required for linear colliders.

Since last year, the development in the world landscape related to the linear collider has come to bring renewed interests in ATF. An obvious area of research is to respond to the demanding performance requirements for the ILC damping rings, including the development of very fast kickers. Yet another interest exists in exploiting the ultra-low emittance beam of ATF for studying the issues related to the final focus system at ILC.

Simulation studies indicate that by applying the beam optics design, which would be used at the ILC final focus system (FFS), the ATF beam can be transversally focused down to approximately 40 nanometer in its extended beam extraction line called ATF2. This exercise, studies tell, would provide the scientists with a wealth of practical experience and detailed information on how to "do it right" with the real-life ILC FFS.

Thus the scientists and the leaders around ATF decided to reorganize themselves and to launch a new international collaboration during this past summer to pursue these subjects in ways which could mimic how we might pursue the ultimate ILC project. The collaboration is based on a multi-lateral MoU (Memorandum of Understanding), which has been signed by many institutes from Asia, Europe and North America, and more institutes are expected to join. The text of the MoU is available for viewing at http://atf.kek.jp.

Meanwhile, the ATF2 proposal document, defining the technical contents of this project has been prepared. Volume 1 was published in August, 2005  as KEK Report 2005-2 (also, as CERN-AB-2005-035, CLIC note 636, DESY 05-148, ILC-Asia-2005-22, JAI-2005-002, SLAC-R-771 and UT-ICEPP 05-02). Volume 2 of the ATF proposal document, which outlines the schedule and task assignment of collaborating institutes, is currently being written. Many of the hardware components for ATF2 will be built in 2006-07, and the beam commissioning of ATF2 is expected to start in early 2008.

-- T.Tauchi and J.Urakawa

Tauchi and Urakawa are accelerator physicists at KEK. Urakawa is the spokesperson for the ATF international collaboration. Tauchi is responsible for the construction of the ATF-II beamline.