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[en] The Argonne concept for an accelerator complex for efficiently producing high-quality radioactive beams from ion source energy up to 6-15 MeV/u is described. The Isotope-Separator-On-Line (ISOL) method is used. A high-power driver accelerator produces radionuclides in a target that is closely coupled to an ion source and mass separator. By using a driver accelerator which can deliver a variety of beams and energies the radionuclide production mechanisms can be chosen to optimize yields for the species of interest. To effectively utilize the high beam power of the driver two-step target/ion source geometries are proposed (1) Neutron production with intermediate energy deuterons on a primary target to produce neutron-rich fission products in a secondary ²³⁸U target, and (2) Fragmentation of neutron-rich heavy ion rich fission products in a secondary beams such as ¹⁸O in a target/catcher geometry. Heavy ion beams with total energies in the 1-10 GcV range are also available for radionuclide production via high-energy spallation reactions. At the present time R and D is in progress to develop superconducting resonator structures for a driver linac to cover the energy range up to 100 MeV per nucleon for heavy ions and 200 MeV for protons. The post accelerator scheme is based on using existing ISOL-type 1+ ion source technology followed by CW Radio Frequency Quadruple (RFQ) accelerators and superconducting linacs including the present ATLAS accelerator. A full-scale prototype of the first-stage RFQ has been successfully tested with RF at full design voltage and tests with ion beams are in progress. A benchmark beam, ¹³²Sn at 7 MeV/u, requires two stripping stages, one a gas stripper at very low velocity after the first RFQ section, and one a foil stripper at higher velocity after a superconducting-linac injector

[en] This paper presents the status of accelerator facilities in North America that are involved in research using radioactive nuclear beams (RNB), including existing and operating facilities, ones currently under construction or undergoing major upgrades, and ones being planned or proposed for the future. Existing RNB facilities are located at TRIUMF (TISOL) in Vancouver, B.C., the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory, the Argonne Tandem Linear Accelerator System (ATLAS) at Argonne National Laboratory, the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University, the Nuclear Structure Laboratory at The University of Notre Dame, the 88 Cyclotron at Lawrence Berkeley National Laboratory, and the Cyclotron Institute at Texas A and M University. Currently, there are two major RNB facility upgrades in progress in North America, one at TRIUMF, the ISAC project, and one at NSCL the Intensity Upgrade project. For the future the U. S. Nuclear Science Advisory Committee has given high priority for an advanced RNB facility of the ISOL type. Concepts for such a facility, currently being developed at Argonne National Laboratory and Oak Ridge National Laboratory, are presented. Plans are also being developed in Canada at TRIUMF for a major upgrade of the ISAC facility

[en] Next-generation high-intensity large acceptance fragment separators require a careful design due to the large high order aberrations induced by the large aperture superconducting magnets needed to collect rare isotopes obtained from a high energy primary heavy-ion beam hitting a target. In this paper we propose a fragment separator layout based on various symmetries that satisfies the baseline requirements. Analytical calculations based on symmetry theories simplify the design to numerical optimization of a basic cell with only a few magnetic elements. The insight provided by these calculations resulted in the specification of a simple layout with large acceptance, transmission, and resolution. The design method may be easily adapted to project-specific needs. The important effects of energy degraders necessary for full fragment separator design will be addressed in a future publication

[en] Monte Carlo simulations of the low- and high-conductivity Target/Ion Source systems used at Oak Ridge National Laboratory for effusion measurements are performed. Comparisons with the corresponding experimental data for the different geometries are presented and discussed. Independent checks of the simulation using data for simple geometries and using the conductance approach well known in vacuum technology are performed. A simulation-based comparison between the low- and high-conductivity systems is also presented

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[en] A second order analytical and an arbitrary order numerical procedure is developed for the computation of transfer maps of energy degraders. The incorporation of the wedges into the optics of fragment separators for next-generation exotic beam facilities, their optical effects, and the optimization of their performance is studied in detail. It is shown how to place and shape the degraders in the system such that aberrations are minimized and resolving powers are maximized

[en] This paper presents the development of a parallel three-dimensional Poisson solver in cylindrical coordinate system for the electrostatic potential of a charged particle beam in a circular tube. The Poisson solver uses Fourier expansions in the longitudinal and azimuthal directions, and Spectral Element discretization in the radial direction. A Dirichlet boundary condition is used on the cylinder wall, a natural boundary condition is used on the cylinder axis and a Dirichlet or periodic boundary condition is used in the longitudinal direction. A parallel 2D domain decomposition was implemented in the (r,θ) plane. This solver was incorporated into the parallel code PTRACK for beam dynamics simulations. Detailed benchmark results for the parallel solver and a beam dynamics simulation in a high-intensity proton LINAC are presented. When the transverse beam size is small relative to the aperture of the accelerator line, using the Poisson solver in a Cartesian coordinate system and a Cylindrical coordinate system produced similar results. When the transverse beam size is large or beam center located off-axis, the result from Poisson solver in Cartesian coordinate system is not accurate because different boundary condition used. While using the new solver, we can apply circular boundary condition easily and accurately for beam dynamic simulations in accelerator devices

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No abstract available