Advent of electron synchrotrons created tremendous opportunities in photon associated sciences. However, the initial utilization of light depended on the accelerators built for other purposes, namely, the high energy physics, so that the access was limited mostly in parasitic modes.

Japanese synchrotron radiation users had thus undertaken building an electron storage ring as a dedicated light source as early as 1965, and the construction started in 1970. The first successful storage was accomplished in late 1974, thus the machine “SOR–RING” had become the first purposely built electron accelerator for synchrotron radiation research. It was also unique in that the machine was built mainly by radiation users. The motivations, the processes of construction, and achievements are described.

A new electrostatic ion storage ring (TMU E-ring) has been constructed by collaboration of atomic physics and cluster chemistry groups in Tokyo Metropolitan University. The compact-sized ring has a race-track-type shape of about 7.7 m in circumference, and is able to store the ions of the energy up to 20q keV. Large molecular/cluster ions are stored taking an advantage that the electrostatic ion storage ring is free from the limit of mass of circulating ions. The region of the ion trajectory is cooled down to the liquid nitrogen temperature to quench vibrationally excited ionic states of large molecules through infrared radiation.We have started the lifetime measurement of meta-stable molecular ions as well as the laser spectroscopy of huge molecular ions adopting a visible tunable laser.

Recent progress and perspectives of laser-plasma acceleration of electrons are given. The short history is first given, and the subject is reviewed in such terms as plasma creation, plasma wave generation, test beam generation, mono-energetic beam generation, plasma wave decay, and staging of injection and acceleration. Recent topics such as direct acceleration, forced laser wake field acceleration, bubble or cavity formation, quasi-mono-energetic beams, etc. are included.

A russian researcher shares his Impressions about life in Japan

Recently accelerating gradient with superconducting RF cavity has been very much upgraded up to 50MV/m. It took more than twenty years. In this paper, the battles on various materials/surface scientific issues in the those two decades are historically reviewed on the long term cavity R&D.

The electron linac at Hokkaido University still works well and it is used in various fields of the research although its age is more than 30 years. Here, I introduce briefly the activity using the linac concerning beam monitor, pulse radiolysis and parametric X-ray, and finaly its application to neutron science field in more detail.

Since Cyclotron and Radioisotope Center was established in 1977 for multi-purpose use of cyclotron at Tohoku University, the cyclotron has been used mainly for the studies of nuclear physics and nuclear medicine using Positron Emission Tomography (PET). The PET study has been much developed at Tohoku University by the collaboration of medical scientists with physicists. The contribution of physicists to the development is briefly presented here.

Updated status of compact and advanced-compact medical accelerator development is reviewed. In their applications, medical physics and medical physicist are necessary. Their educational programs have started in several universities and institutes. As one important new trend on life-science, the research on the synergy of DDS (Drug Delivery System) and physical energies are proposed.

The Siam Photon Project is a project conducted by the National Synchrotron Research Center (NSRC) of Thailand to construct a synchrotron radiation facility at Nackhon Ratchasima in Thailand, which is based upon the accelerator system donated by SORTEC Corporation in Japan. The project began in 1996 and it was practically directed by Professor Takehiko Ishii till 2005. This article describes, from a view point of a Japanese accelerator physicist, when and how the SORTEC accelerator system was dismantled and transported from Japan to Thailand, the building of the Siam Photon Laboratory was constructed, the Siam Photon Source was assembled and commissioned, and performance of the accelerator system was improved in these 10 years.