The upcoming Facility for Rare Isotope Beams (FRIB) at Michigan State University provides a new opportunity to access some of the world’s most specialized scientific resources: radioisotopes. An excess of useful radioisotopes will be formed as FRIB fulfills its basic science mission of providing rare isotope beams. In order for the FRIB beams to reach high-purity, many of the isotopes are discarded and go unused. If harvested, the unused isotopes could enable new research for diverse applications ranging from medical therapy and diagnosis to nuclear security. Given that FRIB will have the capability to create about 80% of all possible atomic nuclei, harvesting at FRIB will provide a fast path for access to a vast array of isotopes of interest in basic and applied science investigations. To fully realize this opportunity, infrastructure investment is required to enable harvesting and purification of otherwise unused isotopes. An investment in isotope harvesting at FRIB will provide a powerful resource for development of crucial isotope applications. In 2010, the United States Department of Energy Office of Science, Nuclear Physics, sponsored the first ‘Workshop on Isotope Harvesting at FRIB’, convening researchers from diverse fields to discuss the scientific impact and technical feasibility of isotope harvesting. Following the initial meeting, a series of biennial workshops was organized. At the fourth workshop, at Michigan State University in 2016, the community elected to prepare a formal document to present their findings. This report is the output of the working group, drawing on contributions and discussions with a broad range of scientific experts.

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Imagine being able to predict -with unprecedented accuracy and precision -the structure of the proton and neutron, and the forces between them, directly from the dynamics of quarks and gluons, and then using this information in calculations of the structure and reactions of atomic nuclei and of the properties of dense neutron stars (NSs). Also imagine discovering new and exotic states of matter, and new laws of nature, by being able to collect more experimental data than we dream possible today, analyzing it in real time to feed back into an experiment, and curating the data with full tracking capabilities and with fully distributed data mining capabilities. Making this vision a reality would improve basic scientific understanding, enabling us to precisely calculate, for example, the spectrum of gravity waves emitted during NS coalescence, and would have important societal applications in nuclear energy research, stockpile stewardship, and other areas. This review presents the components and characteristics of the exascale computing ecosystems necessary to realize this vision.Nuclear physics research and its applications, more than many other areas of science, rely heavily on large-scale, high-performance computing (HPC). HPC is integral to (1) the design and optimization of an extensive and vibrant experimental program, (2) acquisition and handling of large volumes of experimental data, and (3) large-scale simulations of emergent complex systems -from the subatomic to the cosmological. Dramatic progress has already been made in enhancing our understanding of strongly-interacting matter across many areas of physics: from the quark and gluon structure of the proton and neutron, the building blocks of atomic nuclei; to relating the hot dense plasma in the early universe to the near-perfect fluid produced at the Relativistic Heavy Ion Collider (RHIC); to the structure of rare isotopes and the reactions required to form all the elements of the universe; to the creation and properties of the dense cold matter formed in supernovae and NSs.In addition to pursuing new analytical and experimental techniques and algorithms and more complete physical models at higher resolution, the following broadly grouped areas relevant to the U.S. Department of Energy (DOE) Office of Advanced Scientific Computing Research (ASCR) and the National Science Foundation (NSF) would directly affect the mission need of the DOE Office of Science (SC) Nuclear Physics (NP) program.Exascale capability computing and associated capacity computing will revolutionize our understanding of nuclear physics and nuclear applications.Closely tied to the needs for exascale hardware are the requirements for new software (codes, algorithms, and workflows) appropriate for the exascale ecosystem, which can be developed through collaborations among ASCR and NSF mathematicians and computer scientists and NP scientists.

The SPIRAL2 project, currently under construction at GANIL, will include an isotope separator on line based facility for the production and acceleration of radioactive ion beams. A superconducting linear accelerator will accelerate 5 mA deuterons up to 40 MeV and 1 mA heavy ions up to 14.5 MeV/u. These primary beams will be used to bombard both thick and thin targets. We are investigating three different techniques to produce the radioactive ion beams: (1) the neutron induced fission of uranium carbide, (2) the direct interaction of deuterons in a uranium carbide target, and (3) the interaction of a heavy ion beam with a target. All these production systems will be coupled to an ion source. Four kinds of ion sources are foreseen for the ionization of the radioactive atoms: an electron cyclotron resonance ion source, a surface ionization ion source, a forced electron beam induced arc discharge ion source, and a laser ion source depending on the characteristics of the desired radioactive ion beam in terms of intensity, efficiency, purity, etc. A presentation of the SPIRAL2 project and of the different production systems is given.

The production of singly charged atomic and molecular ions with a new 2.45 GHz electron cyclotron resonance ion source has been studied. The ion source Mono 1000 uses a new magnetic confinement structure. The elements Ne, Ar, and Kr are ionized with efficiencies close to 100%, while 45% has been achieved for He. In the case of the molecules SO2 and SF6, more than 90% overall efficiency has been observed with more than 40% of sulfur atoms leaving the source under the form S+. A total extracted yield of 4×1012 singly charged fulleren (C60) ions per second has also been observed.

International audienceTwo new target-source systems have been realized and used to produce radioactive elements with primary beams of 78Kr (68.5 A MeV) and 36Ar (95 A MeV). The production yields of 73,72Kr, 35,33,32Ar, 30,29P, 31,30S, 34,33,32Cl and of some other condensable elements such as 73,72Br and 73,71Se are presented. The results of the improvements between the two versions of the production system are discussed