Rare Isotope Accelerator Project Research Articles

Rare isotope accelerator project in Korea and its application to high energy density sciences

As a national science project, the Korean government has recently established the Institute for Basic Science (IBS) with the goal of conducting world-class research in basic sciences. One of the core facilities for the IBS will be the rare isotope accelerator which can produce high-intensity rare isotope beams to investigate the fundamental properties of nature, and also to support a broad research program in material sciences, medical and biosciences, and future nuclear energy technologies. The construction of the accelerator is scheduled to be completed by approximately 2017. The design of the accelerator complex is optimized to deliver high average beam current on targets, and to maximize the production of rare isotope beams through the simultaneous use of Isotope Separation On-Line (ISOL) and In-Flight Fragmentation (IFF) methods. The proposed accelerator is, however, not optimal for high energy density science, which usually requires very high peak currents on the target. In this study, we present possible beam–plasma experiments that can be done within the scope of the current accelerator design, and we also investigate possible future extension paths that may enable high energy density science with intense pulsed heavy ion beams.

A 57-MHz CW RFQ for the AEBL Project

The Advanced Exotic Beam Laboratory (AEBL) at the Argonne National Laboratory (ANL) will provide a research facility for studies of nuclear phenomena by using beams of short-lived isotopes for research in the nature of nucleonic matter, the origin of the elements, tests of the Standard Model along with applications in medicine, industry, and other applied physics research. The proposed design of the AEBL driver linac evolved from the Rare Isotope Accelerator (RIA) project. It is a CW 850 MV linac capable of accelerating uranium ions up to 200 MeV/u and protons to 570 MeV with 400 kW beam power. The first section of the linac is a 57 MHz pseudo split coaxial CW Radio Frequency Quadrupole (RFQ) linac. This is followed by 221 superconducting cavities of various types. A section of the RFQ linac was fabricated and tested under R&D funding for the RIA Project. This is the first section of the six-section, 392 cm RFQ linac. This paper describes the design, fabrication, and testing of this RFQ.

Rare Isotope Accelerator (RIA) Project

The proposed Rare Isotope Accelerator (RIA) Project will provide world-class intensities of radioactive beams created by any of the known production mechanisms. A driver linac will be used to accelerate any stable isotope from protons through uranium to energies of ⩾400 MeV/u and intensities of ⩾100 kW. Lighter elements will be used to produce radioactive ion beams by the isotope separation on line (ISOL) method. Typically heavier elements will be used to produce radioactive ion beams by the particle fragmentation (PF) method. A hybrid method of stopping radioactive ion beams produced by the PF method in a gas cell will also be employed. The RIA project has strong support from the nuclear science community as evidenced by RIA being the highest priority for major new construction in the most recent Nuclear Science Advisory Committee (NSAC) Long Range Plan [2002 NSAC Long-Range Plan: Opportunities in Nuclear Science, A long-range plan for the next decade, April 2002]. In addition, RIA is tied for third position for the near term priorities of the Department of Energy (DoE) 20-year plan [DOE Office of Science, Facilities for the future of science: a twenty-year outlook. http://www.sc.doe.gov/Sub/Facilities_for_future/facilities_future.htm]. The status of the RIA design is presented.

Neutronics and radiation field studies for the RIA fragmentation target area

Neutronics simulations and activation evaluations are currently in progress as part of the pre-conceptual research and development effort for the Rare Isotope Accelerator (RIA). The RIA project involves generating heavy element ion beams with powers up to 400 kW for use in a fragmentation target line to produce selected ion beams for physics research experiments. Designing a fragmentation beam dump for RIA is one of the most critical challenges for such a facility. Here, we present the results from neutronics and radiation field assessments for various beam dump concepts that can meet requirements for the RIA fragmentation line. Preliminary results from heavy ion transport including radiation damage evaluations for the RIA fragmentation beam dump are also presented. Initial neutronics and activation studies will be incorporated with other target area considerations to identify important challenges and explore possible solutions.

Heavy-ion beam dynamics in the RIA accelerators

The Nuclear Science Community in the United States has unanimously concluded that developments in both nuclear science and its supporting technologies make building a Rare-Isotope Accelerator (RIA) facility for production of radioactive beams. The RIA development effort involves several US Laboratories (ANL, JLAB, LANL, LBNL, MSU, ORNL). The RIA project includes a continuous wave 1.4 GV driver linac and a 123 MV post-accelerator, both based on superconducting (SC) cavities operating at frequencies from 48 to 805 MHz. Several new conceptual solutions in physics design of heavy-ion SC linacs have been developed recently. In particular, the concept of multiple charge state beam acceleration in SC linacs was tested and will be used in the driver linac to increase available accelerated beam power. A detailed design has been developed for the focusing–accelerating lattice of the RIA linacs which are configured as an array of short SC cavities, each with independently controllable RF phase. Independent phasing allows the velocity profile to be varied: the linac can be tuned to provide higher energies for the lighter ions. For example, the reference design linac can be tuned to provide a uranium beam at an energy of 403 MeV/ u and can be re-tuned to provide a proton beam at 900 MeV. The linac must provide 100 kW beam power with the possibility to upgrade up to 400 kW.

Heavy-ion LINAC development for the US RIA project

The Nuclear Science Community in the Unites States has unanimously concluded that developments in both nuclear science and its supporting technologies make building a world-leading Rare-Isotope Accelerator (RIA) facility for production of radioactive beams the top priority. The RIA development effort involves several US Laboratories (ANL, JLAB, LBNL, MSU, ORNL). The RIA facility includes a CW 1.4 GeV driver LINAC and a 100 MV post-accelerator both based on superconducting (SC) cavities operating at frequencies from 48 MHz to 805 MHz. An initial acceleration in both LINACs is provided by room temperature RFQs. The driver LINAC is designed for acceleration of any ion species; from protons up to 900 MeV to uranium up to 400 MeV/u. The novel feature of the driver LINAC is an acceleration of multiple charge-state heavy-ion beams in order to achieve 400 kW beam power. Basic design concepts of the driver LINAC are given. Several new conceptual solutions in beam dynamics, room temperature and SC accelerating structures for heavy ion accelerator applications are discussed.

Production of low- and high-energy radioactive-ion beams by fragmentation

The physics opportunities made possible by beams of rare isotopes are among the richest available in nuclear science. The rare-isotope accelerator (RIA) now under development is an innovative accelerator that will define the state of the art for all such facilities. A novel aspect of the RIA project is the conversion of the most intense high-energy heavy-ion beams into both fast and reaccelerated exotic beams. Along with target fragmentation in next-generation high-power ISOL targets, RIA will use projectile fragmentation in a high-energy separator/gas-filled ion collector system to provide an extensive range of thermalized ions for reacceleration. In addition, a second high-energy separator will provide the same or larger range of ions for high-energy experiments. A brief overview of the RIA accelerator concept, the layout of the facility, and production techniques will be given along with information on the present R&D efforts in gaseous-ion collection.