Research activities of physics with radioactive isotope beams are reviewed and its global expansions are presented. Introduced are the subjects of physics with radioactive nuclei and the history of the in-flight facilities, especially for conceptual ideas in designing Radioactive Isotope Beam Factory (RIBF). Special emphasis is given to selected research highlights at RIBF and future directions are discussed.
The BigRIPS fragment separator is the core experimental device at RIKEN RIBF and used to produce a large variety of radioactive isotope beams based on the in-flight separation technique. A total of 1460 isotopes have thus far been produced for 184 experimental programs using in-flight fission of a uranium beam as well as projectile fragmentation of stable beams since it became operational in March 2007. The number of new isotopes produced and identified at BigRIPS has reached 142 for about 13 years of operation. Research and development activities for more efficient production of high-intensity and more exotic RI beams have been launched.
RIKEN RI Beam Factory, aiming at delivering various heavy-ion beams with high intensities, has been steadily developing its performance after its beam commissioning in 2006. Characteristic features of RI Beam Factory, a history of its performance upgrade especially for the uranium beam intensity and the present performance will be summarized in this report.
The electron cyclotron resonance (ECR) ion source is one of the best ion sources to use as an external ion source of the accelerator complex for the radio-active isotope beam factory. The performance of the ECR ion source has been rapidly improved in the last three decades. Especially, in the last decade, it was dramatically improved to meet the requirements for the super-heavy element search experiment and the intense radio-active isotope beam production. At RIKEN, superconducting ECR ion sources with 28 GHz microwaves were constructed to produce intense metallic ions beams (U, V etc.) for these purposes. In this article, I describe the status of the ECR ion source at RIKEN and the effect of main parameters of the ion source (magnetic field distributions, microwave frequency and power, gas pressure etc.) on the plasma and beam intensity of highly charged heavy ions. Based on these results, I briefly present how to produce more intense beam of heavy ions with the ECR ions source.
Charge stripping process is almost indispensable for efficient accelerations of particularly heavy ions such as uranium in heavy-ion accelerator complex. At the RIKEN RI beam factory (RIBF), the total charge stripping efficiency of two strippers, He gas and rotating graphite sheet disk strippers, used for the uranium acceleration is less than 5% which is a serious bottleneck for further intensity upgrade. We have proposed a novel acceleration scheme with charge stripper rings (CSRs) to increase the charge stripping efficiency as a promising future plan at the RIBF. In this paper, we present some results of calculations on key design issues of the CSR.
Facility for Rare Isotope Beams (FRIB) is based upon a driver linac to accelerate all stable isotope beams with a beam energy above 200 MeV/u and a beam power up to 400 kW. The linac has already delivered the beams meeting the Key Performance Parameter (KPP) of project completion defined by US Department of Energy (DOE). This article is focused on the beam commissioning results achieving this KPP and the beam study results beyond the KPP. The project team is now being engaged in completion of target systems including the beam dump, the pre-separator and experimental area reconfiguration. The project is thus on track for user runs scheduled early 2022. The beam power will be ramped up to the goal of 400 kW during the course of several years as J-PARC and SNS. Another focus of the project is to develop technologies for the power ramp up such as the liquid lithium charge stripper.
An international accelerator complex FAIR is being constructed in the site of Helmholtz Association Institute GSI, Darmstadt, Germany. After reevaluation of the project and review process in 2015 and 2019, the project is dynamically progressed. Civil construction of the FAIR north part, where the heavy ion synchrotron SIS100 is located, is well advanced. Series production and cryogenic testing of the superconducting dipole magnets for SIS100 will be completed beginning of 2021. Civil construction of south part of FAIR including a fragment separator Super-FRS was started. The first superconducting magnet module for Super-FRS was manufactured and tested at a dedicated cryogenic test facility at CERN. Status of the project and future plan are presented.
The beginning of the construction of the next-generation accelerator facility—High Intensity heavy ion Accelerator Facility (HIAF)— of Institute of Modern Physics, Chinese Academy of Sciences, in Huizhou, Guangdong Province, China, in December, 2018 marked a new chapter in the accelerator-based science in China. Together with the China initiative Accelerator Driven System (CiADS), HIAF will propel research in accelerator sciences in China, and provide vast research opportunities in various fields covering nuclear physics, atomic physics, nuclear chemistry, biology as well as material, medical and space sciences to worldwide users.
RAON, being constructed as the Rare Isotope Science Project (RISP) by the Institute for Basic Science (IBS) since 2011 is a flagship heavy ion accelerator facility in Korea to promote fundamental science and application of isotope nuclei and related science.1–3) Civil construction of the RAON site in Shindong, Daejeon of Korea, is going to finish in 2021 and installation of the heavy ion accelerator systems including injector, rare isotope (RI) production systems, and experimental systems are currently being progressed toward to commissioning of RAON. The overview RAON accelerator facility and status of RISP are reported in this paper.