The first accelerator symposium “Accelerator in your life” was held on Monday, May 27, 2024 at Kudan Kaikan Terrace Akane-no-Ma in Tokyo. This symposium was planned to take the opportunity of the incorporation of the Particle Accelerator Society of Japan as a general incorporated association to consider once again the relationship between accelerator researches and society. The first half of the symposium featured lectures by Goki Inada, Director for Research Environment Division, Science and Technology Policy Bureau, Ministry of Education, Culture, Sports, Science and Technology, and Mitsuru Uesaka, Chairperson of Japan Atomic Energy Commission, Cabinet Office, and the second half featured a panel discussion. Many interesting discussions were held on accelerators and their issues that are active in society, providing important suggestions for future society activities.

The Japan Atomic Energy Commission (JAEC) developed the Action Plan that aims to provide domestic radioisotopes to patients in May, 2022 via JAEC’s advisory committee on Medical Radioisotopes, the expert subcommittee operation from November, 2021. The goals to be achieved during next decade are; ①Establishment of a Stable Radioisotope Diagnostic System through partial domestic production of Mo-99/Tc-99m, ②Implementation of Radioisotope Treatment Using Domestic Radioisotopes, ③Dissemination of Radioisotope Treatment in Medical Setting, ④Making Radioisotope-Related Fields, centered on Medicine, as a “Strength” of Japan. The JAEC is steadily following up on the efforts of relevant ministries and agencies and each stakeholder based on this Action Plan, and continues to take the leadership in promoting it.

KEK B-factory (KEKB) was a project to pursue a luminosity frontier of high energy physics after the energy frontier by TRISTAN. KEKB was designed making use of experiences during TRISTAN as a stepping-stone. From the experience of designing and operating the KEKB vacuum system, some topics of concern in those days are picked up and summarized. They are, synchrotron radiation, one-dimensional molecular flow, and the density measurement of electron cloud.

The electron-positron injector at KEK has been delivering beams for both particle physics and synchrotron radiation science experiments for many years. To increase the efficiency of these experiments, we have been developing simultaneous top-up injection with fast beam switching. In particular, to meet the stringent beam conditions required for the SuperKEKB B-Factory project, a large number of pulsed-operated devices have been developed over a long period of time. These devices are coordinated by a high-speed wide-area event synchronization mechanism, enabling beam switching 50 times per second. During the full-scale beam commissioning of SuperKEKB in 2019, simultaneous top-up injection into five multipurpose storage rings was achieved. This led to more than 200% increase in the efficiency of particle physics experiments and improved the stability of the stored beam current of synchrotron radiation experiments to less than 0.1% fluctuation. The concept and development details of this project are described.

We have started a new platform for the support of the scientific research in many fields of science by the supply of short-lived radioisotopes and the technical support of their treatment. In this framework, many kinds of research projects which are not supported by the JSPS Grant-in-Aid (KAKENHI) are supported. Scientific research in the early stages and collaboration with industrial sector can be supported from this new platform. We plan to increase our human resources and focus on providing technical support and research consulting. We also plan to add new nuclides in our suppliable RI list. We aim at the promotion of scientific research using short-lived radioisotopes.

A quarter century has been passed since the discovery of high energy proton beam from the interaction between high intensity laser pulse and solid density targets. However, the controllability of the beam is not good enough for being used in many applications. Although high energy ion beam is desired from many fields of applications, proton with energy greater than 100 MeV was not easily accelerated. We show that the laser temporal pulse condition is a key for controlling the ion acceleration performance and demonstrated for the first time that the same ion acceleration performance is reproduced in two independent PW-class laser systems by tuning the temporal pulse condition exactly same. Furthermore, with even careful controlling of the laser temporal pulse condition, ～150 MeV proton beam is obtained by only 22 J laser on target, which is the world record so far.

In vacuum chambers and accelerating cavities in recent accelerators, RF absorbing materials are widely used for damping higher-order modes and reducing the coupling impedance. For precisely measuring the RF characteristics of absorbing materials, we developed a new resonant-cavity method for measuring RF absorbing materials. In our method, the cavity-eigenmode simulation is used to evaluate the complex permittivity or permeability of a sample from the results of RF measurements. We fabricated a rectangular cavity for this method and measured the complex permeability of a ferrite sample in frequency range of 1.5–3 GHz. The result was compared with one from the Nicolson-Ross-Weir method.

Accelerator Reliability Workshop 2024 (ARW2024) was held at Helsingborg in Sweden from 23 to 28 June 2024. In the workshop, many topics related to the reliability and operation were discussed through oral sessions, poster sessions, and breakout sessions by 173 participants. Next workshop (ARW2026) will be held in Aomori, Japan in 2026.