The community of the high energy physics recently adopted the superconducting technology for the ILC (International Linear Collider). This will bring about a new phase of the linear collider development. An international design group will be formed in early 2005, aiming at the machine completion in the mid 2010’s.

In 1995, a comprehensive beam study was accomplished in KEK–PS in order to achieve more than two times larger beam intensity for K2K experiment. Accoding to the intensity upgrade, some phenomena caused by a space charge effect were observed. The survey results of operating point with respect to the resonance and chromaticity are introduced in this report.

A fast, non-destructive beam-profile monitor was developed using an oxygen gas-sheet target in the HIMAC synchrotron. The size of the gas-sheet target was 85 mm in width and 1.3 mm in thickness, of which the density was 1×10⁻⁴ Pa. The base vacuum in the ring was not deteriorated by this gas-sheet target, and was on the order of 10⁻⁸ Pa. In typical cases, carbon ion beams are accelerated from 6 to 290–430 MeV/n for cancer therapy, in which the intensity is 2.5×10⁸ particles/bunch. For these beams, two-dimensional beam profiles were successfully measured within the time (～100 ns) of the bunch separation. This article describes both the technical and physical aspects of the monitor together with some results.

Maintenance and upgrading of the KEK proton linear accelerator for 30 years are described. The linac was substantially the first Drift Tube linac in Japan. It started with pulsed quadrupole magnets, then permanent quadrupole magnets were developed for easy maintenance. The linac was upgraded from 20 MeV to 40 MeV by introducing a new accelerating tank. It was equipped with the permanent quadrupole magnets. For the old tank, control system of the quadrupole magnet power supplies were fully modified. High-power dummy loads of 200 MHz accelerating rf were improved. Trials were made to avoid slow leaks of ceramic windows that transfer rf power up to 1.5 MW to the accelerating tank. Other miscellaneous components, such as vacuum system, cooling water, pulse generators and so on, were upgraded.

I have been a fellow of the JSPS at KEK for 2 years. This fellowship has given me the opportunity to see how research is conducted in a Japanese research institute and to compare with my experience in Europe. My stay in Japan has also been an opportunity for me to discover a different culture.

Succeeding the symposium on “Research and Development of Accelerators in Atomic Energy Field” held in Aug. 7–8, 2001 at the Reactor Research Institute (RRI), Kyoto University, so-called, the second work-shop was held in Aug. 10–11, 2004 at the same RRI to discuss the present status and future plan in the R & D on accelerator itself and their applications. Over 50 participants from 26 research laboratories in Japan were joined. New data of all the participated facilities were reported and hot discussions were performed. Here, the report on this symposium is described with the author’s private conception to open this symposium.

We have developed a digital RF control system with DDS (Direct Digital Synthesizer) for HIMAC (Heavy IonMedical Accelerator in Chiba) synchrotron. In advance, this control system with beam feedbacks was tested in TARN–II ring successfully with very low beam intensity. Now, this tested acceleration system is operating in HIMAC synchrotron with good condition; we found there is no need to use the tested beam feedback system.

This report presents the present status of 46 MeV electron linear accelerator (linac) of the Research Reactor Institute, Kyoto University (KURRI) and also reviews how the linac has been successfully used/operated for 40 years. Precious experiences in the linac maintenance are introduced: how to solve the overload of klystron modulator, development of a fast pulser for an electron gun, and how to make the maintenance effective.

Nishina Memorial Cyclotron Center (NMCC) has been opened for nationwide-common utilization of positron nuclear medicine (PET) and PIXE (Particle Induced X-ray Emission analysis) since April 1993. Sufficient amount of 2.9-MeV protons can be extracted from a small-size cyclotron, which was established exclusively for PET, by accelerating H⁺₂ -ions with acceleration parameters for 8.3-MeV deuterons. At the present time, nearly 40 subjects of PIXE and 15 subjects of PET have been pursued here. Especially for PIXE, many subjects in various research fields have been studied at our facility. More than 60,000 samples have already been analyzed up to the present, and nearly 75% of them are samples in the field of life-science. The total number of samples in each research field is about 45,000 for life science, 10,000 for the other research fields and 5,000 for technical development. International projects for investigating human exposure to toxic elements caused by wide-aerial contamination are also described as a topic.