Since coherent synchrotron radiation (CSR) from short bunches of electrons was first observed in 1989, several types of coherent radiation have been studied experimentally using linear accelerators. Recently, the CSR has been also observed at storage rings and an energy recovery linac. It is useful tool not only for the diagnosis of an electron beam but also for the light source in the terahertz region.

For the purpose of describing the dynamics of off-momentum particles in strong focusing ring accelerators with strong sextupole magnets, it is indispensable to know the higher order dispersion and chromaticity. Hence we established the Hamiltonian Formalism of non-linear dispersion and chromaticity of circular accelerators and gave the perturbative formulae explicitly. In this paper we review the outline of the Hamiltonian Formulation of the dispersion and the chromaticity.

A new phase of laser acceleration research has entered, as signified by the recent reports in Nature 9/30/05 of the generation of quasi-monoenergetic electron beam by laser wakefield acceleration in three experiments. We survey the current status of experiments and offer their theoretical interpretation. We understand why the choice of parameters is of such importance and why the earlier experiments showed energy spectra far from monoenergy.

The JAERI free-electron laser (FEL) driven by a compact, energy recovery superconducting rf linac (ERL) has been developed to realize simultaneously a tunable over the mid-infrared (MIR) and far-infrared (FIR) wavelength regions, ultra-short pulse of 255 fs, highly-effecient of 6–9 percents, high-peak power of 1 GW, and high average power of over 2 kW. Here, we briefly describe the JAERI FEL facility and characteristics of the FEL device and ERL driver, and report the 10kW high average power FEL demonstration under way, industrial applications utilizing the existing and future ERL-FELs, and ERL light source applications near future.

Various obstacles encountered during the course of the construction of the synchrotron radiation facilities in Thailand are described. First background information such as the brief history, the purpose of the project, and the human resources development are mentioned. Then difficulty in promoting the new project is described. Some serious problems having emerged and been overcome in the accelerator construction are mentioned. They are non-uniform floor subsidence, the broken injection timing system, the breaking of newly built vacuum chambers, the unstable operation of the linac, and electrical shortage between layers of coils of quadrupole magnets.

I describe the history of a training system for engineers at KEK, and shortly summarize an article on “the superior engineer” written by Mr. KELLEY of Bell Laboratories. Finally, I give a personal opinion about an ideal engineering method at KEK, in response to decreasing manpower over the next 10 years.

Electron and ion accelerators in a middle to low energy range have been operated for researches in various fields in Research Institute for Advanced Science and Technology, Osaka Prefecture University. Status of the facilities and the future plans are reported.

The Electron Beam Accelerator is one of the most developed machine for industrial use. And it has a wide range of irradiation applications.

Personal reminiscences are told about the first stage of the US-Japan Collaboration which started officially in 1979. The story covers from the time about 15 years before the start of the program through the early 90s when the US SSC project was terminated. Readers would find the great roles of the collaboration program in promoting the research activities of the Japanese high energy community as a whole to its culmination of today.

I have so far visited Korea, PAL (Pohang Accelerator Laboratory) to support the stabilization of the accelerator. This article describes my experience and opinion on research interchange in Asia, particularly in Korea and Japan.