Yamagata University has carried out a heavy ion treatment facility project since 2004. Building and treatment machine has been constructed since 2017. The carbon ion medical accelerator consists of a permanent-magnet type electron cyclotron resonance (ECR) ion source, a series of linear accelerator of radiofrequency quadrupole (RFQ) and interdigital H-mode drift tube linac (IH-DTL) with an energy of 4 MeV/u, and an alternative gradient synchrotron of 430 MeV/u. There are two irradiation rooms, one has a fixed horizontal port and the other has a rotating gantry port with superconducting magnets. Since the irradiation rooms are placed above the accelerator room, the footprint of the building is only 45×45 m, which is significantly smaller than preceding facilities. The synchrotron has a variable-energy flattop operation pattern with 600 energies. This operation enables a three-dimensional spot scanning irradiation without range shifters. A superconducting rotating gantry is equipped with a pair of improved scanning magnets in the downstream of the final bending magnets and is downsized to 2/3 of the first model built in NIRS. The construction of the building was completed in May 2019. The treatment irradiation will start in February 2021 after machine optimization and clinical beam data measurement.
We have developed a compact accelerator-driven neutron facility “AISTANS” at AIST Tsukuba in Japan. This facility is composed of an electron linear accelerator, neutron production source, and neutron beam line. The whole system is optimized for Bragg edge transmission imaging. In this paper, the advantages of neutron spectroscopy, in particular Bragg edge transmission imaging, the basis of the neutron production at AISTANS, and preliminary data are presented.
The rf system of the RIKEN Ring Cyclotron (RRC) was upgraded in order to increase the acceleration voltage at 18.25 MHz operation by remodeling its rf controllers and cavity resonators. As a result, the maximum gap voltage at 18.25 MHz improved from about 80 kV to more than 150 kV. The beam intensity of 238U for the RIBF was increased to 94 pnA in the fiscal 2019 by overcoming the beam intensity limitation due to the space charge effect. It is ready to further increase the beam intensity in the near future.
The 600-m-long KEK injector linac has delivered electron and positron beams for collider rings and light sources. It was upgraded for aiming at a low emittance beam with a high bunch charge towards the SuperKEKB project based on the nano-beam scheme. In this upgrade, many new components have been newly developed, such as a flux concentrator, a large aperture S-band accelerating structure, a pulsed magnet, a low emittance photo-cathode rf gun, a fast rf monitor, a fast BPM module, and so on. After many long years of upgrade work and beam commissioning, simultaneous top-up injection into five independent rings was successfully achieved in 2019.
High intensity proton synchrotrons enable long-baseline neutrino experiments precisely to measure the oscillation probability of the neutrino oscillation phenomenon discovered in 1998. Furthermore, it become possible to search for the particle–antiparticle difference (CP violation) in leptons experimentally by comparing the magnitude of neutrino oscillations between neutrinos and antineutrinos. The recent results from the T2K experiment using J-PARC and Super-Kamiokande show the hints of large CP violation in neutrino oscillations, and provide the first strong limit on the CP violating complex phase. The construction of the Hyper-Kamiokande experiment that aims to detect and measure CP violation in neutrino oscillations in next decade has also started.
Medical radio-isotopes (RI) are commercially produced by accelerators or nuclear reactors. For more than a half century accelerators have routinely produced medical RI used for radiopharmaceuticals in nuclear medicine. Described here is a general introduction of commercial production of medical RI with an accelerator, and recent topics about technical development of use of an accelerator for production of 99Mo and 225Ac. Nihon Medi-Physics has started a project of 99Mo in-house production with an electron linear accelerator since 2019. Alpha emitting nuclide, 225Ac has attracted much attention recently for therapeutic applications based on the concept of Theranostics. 225Ac supply currently relies solely on 229Th generator but alternative production method with an accelerator has been being developed.