In the LLRF system of J-PARC LINAC, the two new digital control systems have been developed and updated for 324-MHz stations. One system utilizes a digitizer box and the existing cPCI analog boards, while the other system incorporates the μTCA.4 system including new analog boards. A stable accuracy of ±0.1% (peak-to-peak) in amplitude and ±0.1 deg. (pp) in phase has been achieved in the absence of beam. To leverage the capabilities of new systems, the open loop transfer functions were calculated. Additionally, an adaptive beam loading compensation system, which was not feasible with the previous digital control system, has been implemented.

The Japan Proton Accelerator Research Complex (J-PARC) Rapid Cycling Synchrotron (RCS) employs magnetic alloy (MA) loaded cavities. We realize multi-harmonic rf driving and beam loading compensation owing to the broadband characteristics of the MA. The conventional type cavity is designed to be driven by tube amplifiers in a push–pull operation. However, some disadvantages arise for the push–pull operation to accelerate the high intensity beam. We have developed a single-ended MA cavity to avoid such disadvantages. The power consumption to drive the cavity can be fairly reduced by using the single-ended cavity.

NanoTerasu is a highly brilliant synchrotron light source mainly focusing on soft to tender X-ray region. The NanoTerasu accelerator system consists of a 3 GeV storage ring based on four bends achromat lattice with a circumference of 349 m and a 3 GeV linear injector accelerator with length of 110 m. The installation of the accelerator system started in Dec. 2021 and successfully finished by the end of May 2023. The commissioning of linear accelerator started on Apr. 17th and a 3 GeV electron beam was successfully delivered to a beam dump in 10 days. The commissioning of storage ring started on June 8th and a 3 GeV electron beam was soon circulated in the storage ring roughly 300 times with storage ring cavity off. The first stored beam was observed on June 18th with storage ring cavity on and the first light from a 3 pole wiggler was observed as well. The present stored electron beam current reaches 200 mA after 40 Ah total dose and preliminary horizontal beam emittance of 1.1 nm.rad under an assumption of 0.097% energy spread is measured with synchrotron radiation from a 3 pole wiggler.

No one doubts that the earth is now in a warming trend. Few people now doubt that natural cycles alone cannot explain it and that global warming gases, including CO₂, are contributing to it. Accelerators are large power load facilities, and it is the duty of those who work on them to set sustainable development goals and ensure that they are implemented. This is difficult to achieve by the efforts of accelerator scientists alone, and requires a broad-based cooperative approach that includes local communities, companies, government, and politics. I would like to start with an analysis of the current situation, understand the global situation, and then propose the issues that we should address.

The International Linear Collider (ILC) project is planned as Asia’s first major international science and technology hub, bringing together researchers from around the world to realize a vision that integrates superconducting technology, large-scale underground facilities, and the harmonious fusion of satoyama (traditional Japanese rural landscapes) with high technology. The ILC Vanguard Initiative was established with the premise of situating the ILC in Japan, collaborating with various organizations across government, industry, academia, and local communities to study the realization of the plan. This includes the construction of a new social model, the creation of new values, and the materialization of the plan. The primary focus of this research group is to advance preparations for urban development related to the future and growth of the prospective site locations, which require extensive surveys, facility reviews, and careful planning. By leading the world in this initiative, Japan aims to create an environment that enables the early realization of the ILC located in Japan. This paper will discuss the overview of the ILC project, focusing on the challenges related to site selection and the efforts of the ILC Vanguard Initiative in addressing these challenges.