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Scandium radioisotopes are increasingly considered viable radiolabels for targeted molecular imaging (Sc-43, Sc-44) and therapy (Sc-47). Significant technological advances have increased the quantity and quality of available radioscandium in the past decade, motivated in part by the chemical similarity of scandium to therapeutic radionuclides like Lu-177. The production and radiochemical isolation techniques applied to scandium radioisotopes are reviewed, focusing on charged particle and electron linac initiated reactions and using calcium and titanium as starting materials.

Production of 99Mo by the 100Mo (γ, n)99Mo reaction through the bremsstrahlung process using an electron accelerator is one of the feasible options currently pursued by several countries. Here we report experimental results on identification of side-reaction products after the irradiation of natural and enriched 100Mo targets. Side-reaction products identified include various Mo, Nb and Zr isotopes. Comparison of experimentally determined reaction production rates with those determined based on theoretical cross-sections will be presented. Moreover, activation products formed due to presence of impurities introduced during the manufacturing of the Mo targets will also be discussed.

In recent years the use of beta-emitting radiopharmaceuticals for cancer therapy has expanded rapidly following development of therapeutics for neuroendocrine tumors, prostate cancer, and other oncologic malignancies. One emerging beta-emitting radioisotope of interest for therapy is

The half-life of 67Cu was determined through serial gamma-ray spectrometry measurements of the dominant gamma emission (E γ : 184.6 keV; branching ratio: 48.7%) produced following β- decay. Data were collected consecutively for 1000 s per measurement, with a total of 3063 measurements over the duration of 36 days. The incidence rate for the 184.6 keV gamma-ray was determined from the spectral peak area and duration of each measurement. This rate was then corrected to account for detector dead-time, radioactive decay during each acquisition and drift in the computer clock in comparison to NIST nuclear clock. Least-squares regression analysis was performed to determine the half-life of 67Cu. The result was 61.761 ± 0.004 h, which is the highest precision measurement to date, and marks a 24-fold precision improvement over the current Nuclear Data Sheets value.

The Super Separator Spectrometer (S3S3) facility is developed in the framework of the SPIRAL2 project [1]. S3S3 has been designed to extend the capability of the facility to perform experiments with extremely low cross sections, taking advantage of the very high intensity stable beams of the superconducting linear accelerator of SPIRAL2. It will mainly use fusion-evaporation reactions to reach extreme regions of the nuclear chart: new opportunities will be opened for super-heavy element studies and spectroscopy at and beyond the driplines. In addition to our previous article (Dechery et al. [2]) introducing the optical layout of the spectrometer and the expected performances, this article will present the current status of the main elements of the facility: the target station, the superconducting multipole, and the magnetic and electric dipoles, with a special emphasis on the status of the detection system SIRIUS and on the low-energy branch which includes the REGLIS3 system. S3S3 will also be a source of low energy radioactive isotopes for delivery to the DESIR facility.

In recent years the use of beta-emitting radiopharmaceuticals for cancer therapy has expanded rapidly following development of therapeutics for neuroendocrine tumors, prostate cancer, and other oncologic malignancies. One emerging beta-emitting radioisotope of interest for therapy is 67Cu (t1/2: 2.6 d) due to its chemical equivalency with the widely-established positron-emitting isotope 64Cu (t1/2: 12.7 h). In this work we evaluate both the imaging and dosimetric characteristics of 67Cu, as well as producing the first report of SPECT/CT imaging using 67Cu. To this end, 67Cu was produced by photon-induced reactions on isotopically-enriched 68Zn at the Low-Energy Accelerator Facility (LEAF) of Argonne National Laboratory, followed by bulk separation of metallic 68Zn by sublimation and radiochemical purification by column chromatography. Gamma spectrometry was performed by efficiency-calibrated high-purity germanium (HPGe) analysis to verify absolute activity calibration and establish radionuclidic purity. Absolute activity measurements corroborated manufacturer-recommended dose-calibrator settings and no radionuclidic impurities were observed. Using the Clinical Trials Network anthropomorphic chest phantom, SPECT/CT images were acquired. Medium energy (ME) SPECT collimation was found to provide the best image quality from the primary 185 keV gamma emission of 67Cu. Reconstructed images of 67Cu were similar in quality to images acquired using 177Lu. Recovery coefficients were calculated and compared against quantitative images of 99mTc, 177Lu, and 64Cu within the same anthropomorphic chest phantom. Production and clinical imaging of 67Cu appears feasible, and future studies investigating the therapeutic efficacy of 67Cu-based radiopharmaceuticals are warranted.

A ~10 µm thick liquid lithium film, flowing at ~50 m s−1 bombarded by a 65 keV, 300 W proton beam was successfully tested at Argonne National Laboratory for the Facility for Rare Isotope Beams (FRIB). An ion source, originally developed for the low energy demonstration accelerator, with a new beam transport system built at FRIB, deposited the proton beam in the lithium film at 43 % of the beam power expected at FRIB when accelerating 400 kW of uranium beam at 200 MeV per nucleon. This technology may also be applicable to other high power target areas.

To support clinical trials for cancer therapy with radiotherapeutic isotopes in the United States reliable sources of adequate quantities of several such isotopes, especially of alpha emitters such as 211At, are a high priority of the DOE Isotopes Program. We have recently tested an alternative reaction, 209Bi(6Li, 4n)211Rn (which decays to 211At) with a 42 MeV 6Li beam from the ATLAS superconducting linac. This latter reaction has the advantage that radon gas is easy to extract and the 14.6-h 211Rn half-life allows more time for transport to the therapy facility. The Bi targets were prepared on a Ni backing as these elements have similar coefficients of thermal expansion, minimizing the chance of target delamination. Helium gas flowed between a thin window and the target to transport the 211Rn it to a charcoal trap. The goal was to develop a method for continuous production and collection of 211At that does not require dissolving the target following each production run. Details of the Bi target production and performance is presented as well as some initial experimental results.

The photonuclear production of no-carrier-added (NCA) 47Sc from solid NatTiO2 and the subsequent chemical processing and purification have been developed. Scandium-47 was produced by the 48Ti(γ,p)47Sc reaction with Bremsstrahlung photons produced from the braking of electrons in a high-Z (W or Ta) convertor. Production yields were simulated with the PHITS code (Particle and Heavy Ion Transport-code System) and compared to experimental results. Irradiated TiO2 targets were dissolved in fuming H2SO4 in the presence of Na2SO4 and 47Sc was purified using the commercially available Eichrom DGA resin. Typical 47Sc recovery yields were >90% with excellent specific activity for small batches (

Charge strippers play a critical role in many high intensity heavy ion accelerators. Here we present some history of recent stripper technology development and indicate the capabilities and limitations of the various approaches. The properties of solid, gaseous, and liquid strippers are covered. In particular, the limitations of solid strippers for high intensity, high atomic number heavy ions and the unique features of helium gas and liquid lithium for high intensity applications are covered. The need for high quality simulation of stripper performance as important input for system optimization is explained and examples of the current simulation codes are given.

We report an approach for preparing refractory nanoporous materials using high surface area silica aerogels as templates for the growth of conformal tungsten (W) coatings by atomic layer deposition (ALD). Nanoporous silica aerogel monoliths were prepared with a variety of initial pore sizes and initial densities in the range of 0.3–0.5 g/cc using porogen extraction methods. Next, W ALD using Si 2 H 6 and WF 6 reactants at 200 °C was employed to coat the inner surfaces of the silica aerogels. After coating, scanning electron microscopy revealed a microstructure in which the ALD W completely encapsulated the silica aerogel micro-cells. The porosity of the aerogels was preserved during the first 10 W ALD cycles allowing the density to be controlled by adjusting the number of W ALD cycles to achieve densities as high as 5 g/cc. Nitrogen adsorption surface area measurements revealed a gradual decrease in the surface area of the silica aerogels with increasing numbers of W ALD cycles, consistent with a partial filling of the aerogel voids. The high density nanoporous tungsten monoliths survived high temperature vacuum heating (1500 °C) making them promising candidates for solid rare-isotope catchers that can be used in the production of short-lived radioactive isotope beams in facilities such as the facility for rare isotope beams (FRIB).

See paper for full list of authors; The Korea Rare Isotope Accelerator, currently referred to as KoRIA, is briefly presented. The KoRIA facility is aimed to enable cutting-edge sciences in a wide range of fields. It consists of a 70 kW isotope separator on-line (ISOL) facility driven by a 70 MeV, 1 mA proton cyclotron and a 400 kW in-flight fragmentation (IFF) facility. The ISOL facility uses a superconducting (SC) linac for post-acceleration of rare isotopes up to about 18 MeV/u, while the SC linac of IFF facility is capable of accelerating uranium beams up to 200 MeV/u, 8 pμA and proton beams up to 600 MeV, 660 μA. Overall features of the KoRIA facility are presented with a focus on the accelerator design.

We present a scheme to use a fragment separator and profiled energy degraders to transfer longitudinal phase space into transverse phase space while maintaining achromatic beam transport. The first order beam optics theory of the method is presented and the consequent enlargement of the transverse phase space is discussed. An interesting consequence of the technique is that the first order mass resolving power of the system is determined by the first dispersive section up to the energy degrader, independent of whether or not momentum compression is used. The fragment separator at the Facility for Rare Isotope Beams is a specific application of this technique and is described along with simulations by the code COSY INFINITY.

An integrated beam optics-nuclear processes framework is essential for accurate simulation of fragment separator beam dynamics. The code COSY INFINITY provides powerful differential algebraic methods for modeling and beam dynamics simulations in absence of beam-material interactions. However, these interactions are key for accurately simulating the dynamics of heavy ion fragmentation and fission. We have developed an extended version of the code that includes these interactions, and a set of new tools that allow efficient and accurate particle transport: by transfer map in vacuum and by Monte Carlo methods in materials. The new framework is presented, along with several examples from a preliminary layout of a fragment separator for a facility for rare isotope beams.

This paper presents the development of parallel direct Vlasov solvers with discontinuous Galerkin (DG) method for beam and plasma simulations in four dimensions. Both physical and velocity spaces are in two dimesions (2P2V) with unstructured mesh. Contrary to the standard particle-in-cell (PIC) approach for kinetic space plasma simulations, i.e., solving Vlasov-Maxwell equations, direct method has been used in this paper. There are several benefits to solving a Vlasov equation directly, such as avoiding noise associated with a finite number of particles and the capability to capture fine structure in the plasma. The most challanging part of a direct Vlasov solver comes from higher dimensions, as the computational cost increases as $N^{2d}$, where $d$ is the dimension of the physical space. Recently, due to the fast development of supercomputers, the possibility has become more realistic. Many efforts have been made to solve Vlasov equations in low dimensions before; now more interest has focused on higher dimensions. Different numerical methods have been tried so far, such as the finite difference method, Fourier Spectral method, finite volume method, and spectral element method. This paper is based on our previous efforts to use the DG method. The DG method has been proven to be very successful in solving Maxwell equations, and this paper is our first effort in applying the DG method to Vlasov equations. DG has shown several advantages, such as local mass matrix, strong stability, and easy parallelization. These are particularly suitable for Vlasov equations. Domain decomposition in high dimensions has been used for parallelization; these include a highly scalable parallel two-dimensional Poisson solver. Benchmark results have been shown and simulation results will be reported.

For charged particle beams that are wider in the dispersive plane compared to the transverse plane it is cost efficient to utilize magnets that accept beams with elliptic cross section. In this paper we presents the conceptual design of a quadrupole magnet with elliptic cross section and with tunable higher order multipoles. The design consists of 18 superconducting race-track coils placed on two hollow concentric rhombic prism support structures. To compute the magnetic field for the proposed design a new method of calculating 2D and 3D fields for the air core magnets based on differential algebra (DA) techniques is developed. We will present the new method and discuss its implementation of new numerical tools based on this method in the code COSY Infinity.

Yield measurements from proton-induced fission have been performed on a number of actinide targets, both Th and U, at the on-line test facility at Oak Ridge National Laboratory. The results are discussed with a focus on the production process and physical and chemical properties of the targets.

International audience; The Super Separator Spectrometer (S3) is a device to be designed for experiments with the very high intensity stable beams of LINAG, the superconducting linear accelerator of GANIL, which will be built in the framework of SPIRAL2. These beams, which will provide in a first phase of SPIRAL2 ions with A/q = 3, can reach intensities exceeding 100 pµA for lighter ones - A

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.

The Office of Science of the Department of Energy is currently considering options for an advanced radioactive beam facility in the U.S. A committee, the Rare Isotope Science Assessment Committee, has been formed under the auspices of the Board of Physics and Astronomy of the National Academies of Science and Engineering with the charge of assessing the importance of and prospects for future research in this field world-wide. There is interest in identifying opportunities for a facility in the U.S. that will complement the capabilities that will exist elsewhere. There is an on-going R&D program sponsored by the DOE to develop the technologies that are essential to both the production of and use of beams of intense exotic beams at next-generation facilities. This paper presents the status of planning and options for such a facility, as well as, progress in the R&D. This program is developing concepts and prototypes for high power superconducting heavy ion linacs for rare isotope production and high power targets, ion sources, fragment separators, gas catchers, and reacceleration technologies that support the delivery of high quality, intense beams of exotic isotopes for research.

The Super Separator Spectrometer S 3 is a major experimental system developed for SPIRAL2. It has been designed for physics experiments with very low cross sections by taking full advantage of the very high intensity stable beams to be produced by LINAG, the superconducting linear accelerator at GANIL. These intensities will open new opportunities in several physics domains using fusion evaporation reactions, principally: super-heavy and very heavy element properties, spectroscopy at and beyond the dripline, and isomer and ground-state properties. The common feature of these experiments is the requirement to separate very rare events from intense backgrounds. S 3 accomplishes this with a large acceptance, a high background rejection efficiency, and a physical mass separation. This article will present the technical specifications and optical constraints needed to achieve these physical goals. The optical layout of the spectrometer will be presented, focusing on technical elements of the target system, the superconducting multipole magnets used to correct high-order optical aberrations, the electric and magnetic dipoles, and the open multipole triplet used for primary beam rejection. The expected system performance will be presented for three experimental cases using 3 specific optical modes of the spectrometer.

Charge-state distributions and energy-loss measurements of uranium ions in gases and solids at incident energies of 60.2 and 200 MeV/u were performed with the magnetic spectrometer FRS at GSI Darmstadt. The charge distribution was investigated in various gases and solids. We observed a gas–solid effect in ionization and mean charge. This effect arises from the shorter collision time in solids comparable with the lifetimes of the excited states of the projectile. Simultaneously, the stopping force was measured for the same targets.

This paper discusses the computational needs for the full design and simulation of the RIA accelerator systems. Beam dynamics simulations are essential to first define and optimize the architectural design for both the driver linac and the post-accelerator. They are also important to study different design options and various off-normal modes in order to decide on the most-performing and cost-effective design. Due to the high-intensity primary beams, the beam-stripper interaction is a source of both radioactivation and beam contamination and should be carefully investigated and simulated for proper beam collimation and shielding. The targets and fragment separators area needs also very special attention in order to reduce any radiological hazards by careful shielding design. For all these simulations parallel computing is an absolute necessity.

Replacing a target transverse to the beam by a 10 times thinner one tilted at about 6o from the beam direction reduces the thickness for heat transfer and diffusion by a factor of 10 while keeping the same production thickness. This concept makes the target cool faster and therefore supports higher beam power. Monte-Carlo effusion simulations of targets based on this concept were carried out to find optimum target geometries for both fast and slow diffusion materials.

There are several nuclear physics laboratories in North America that have on-going research using energetic and stopped radioactive beams. These include the large ISOL-based programs ISAC at TRIUMF in Canada and HRIBF at Oak Ridge and the in-flight fragmentation program at the NSCL of Michigan State University. There are also smaller, more specialized, programs using a variety of techniques at ATLAS at Argonne, the Cyclotron Institute of Texas A&M University, the Nuclear Structure Laboratory at Notre Dame University, the 88-inch cyclotron of Berkeley, and the Nuclear Structure Laboratory at SUNY/Stony Brook. A major upgrade of the NSCL, the Coupled Cyclotron Project, was recently completed, resulting in driver beams at higher energies and intensities than previously available. A major improvement of the ISAC facility is also in progress. ISAC is being upgraded to provide higher energies and a broader range of masses in the ISAC II project with an ECR charge state booster and a superconducting linac to provide energies of 6.5 MeV/u for masses up to A=150. In the United States the construction of a next-generation facility, the Rare Isotope Accelerator (RIA), is being planned. RIA will have a very high-intensity, up to 400 kW, superconducting heavy-ion driver linac which will provide beams from protons to uranium. This facility utilize both ISOL and in-flight production mechanisms. Many laboratories and universities nation-wide are participating in the R&D program for this future facility.

A post-accelerator for rare isotopes (RIB linac) which must produce high-quality beams of radioactive ions over the full mass range, including uranium, at energies above the coulomb barrier is being developed for the U.S. RIA Facility. The linac will accept all ions in the 1+ charge state to provide the highest possible intensity of rare isotopes with masses from 6 to 240. A high-resolution separator to purify beams at the isobaric level precedes the RIB linac. Charge stripping in the linac takes place at two stages: helium gas stripping at 7 keV/u for masses below 132 and 22 keV/u for higher masses, and an additional foil stripping at ∼ 1.1-2.0 MeV/u for the heavier ions. Most of the accelerating voltage in the RIB linac is provided by superconducting resonators. A very-low-charge-state injector, which is needed for the first ∼ 9 MV of the accelerator, will be based on room temperature accelerating structures. This section consists of a pre-buncher followed by three sections of cw RFQ. The first section is a split-coaxial RFQ operating at 12 MHz. The following two sections are hybrid RFQs (H-RFQ) operating at 12 and 24 MHz. A 1:2 scale cold model of the 12 MHz H-RFQ has been built and studied, and has resulted in the development of final specifications for the construction of the full power 12 MHz H-RFQ. Economic design of the RFQs calls for three different types of resonant structures. This paper reports on the present status of the injector design including beam optics and studies of resonant structures.

The high-power heavy-ion beams produced by the Rare Isotope Accelerator (RIA) driver linac have large energy deposition density in solids and in many cases no solid materials would survive the full beam power. Liquid lithium technology has been proposed to solve this problem in RIA. Specifically, a windowless target for the production of radioactive ions via fragmentation, consisting of a jet of about 3 cm thickness of flowing liquid lithium, exposed to the beamline vacuum [1,2] is being developed. To demonstrate that power densities equivalent to a 200-kW RIA uranium beam, deposited in the first 4 mm of a flowing lithium jet, can be handled by the windowless target design, a high power 1 MeV Dynamitron was leased and a test stand prepared to demonstrate the target's capability of absorbing and carrying away a 20kW heat load without disrupting either the 5 mm × 10 mm flowing lithium jet target or the beam line vacuum.

The Rare Isotope Accelerator (RIA) is the highest priority of the nuclear physics community in the United States for a major new facility. RIA is a next generation facility for basic research with radioactive beams that utilizes both standard Isotope-separator On-line (ISOL) and in-flight fragmentation methods with novel approaches to handle high primary-beam power and remove existing limitations in the extraction of short-lived isotopes. A versatile primary accelerator, a 1.4-GV, CW superconducting linac designed to simultaneously accelerate several heavy-ion charge states, will provide beams from protons at 900 MeV to uranium at 400 MeV/u at power levels of 400 kW. The wide variety of primary beams allows various production and extraction schemes to be used to optimize production of specific isotopes. These isotopes, at unprecedented intensities, are available for research at a broad range of energies. They can be delivered at ion source energy for stopped-beam studies, reaccelerated by a second superconducting linac, or directly separated in-flight for use at energies up to 500 MeV/u. The post accelerator uses a unique injection scheme, based on CW low-frequency RFQs, for efficient acceleration of singly charged heavy ions with masses up to 240 amu from ion source energy.

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.

The arbitrary-order map beam optics code COSY Infinity has recently been adapted to calculate accurate high-order ion-optical maps for electrostatic and radio-frequency accelerating structures. The beam dynamics of the superconducting low-velocity positive-ion injector linac for the ATLAS accelerator at Argonne National Lab is used to demonstrate some advantages of the new simulation capability. The injector linac involves four different types of superconducting accelerating structures and has a total of 18 resonators. The detailed geometry for each of the accelerating cavities is included, allowing an accurate representation of the on- and off-axis electric fields. The fields are obtained within the code from a Poisson-solver for cylindrically symmetric electrodes of arbitrary geometry. The transverse focusing is done with superconducting solenoids. A detailed comparison of the transverse and longitudinal phase space is made with the conventional ray-tracing code LINRAY. The two codes are evaluated for ease of optimization, with particular attention to higher-order effects, and future applications are discussed.

The proposed rare isotope accelerator (RIA) facility includes a post-accelerator for rare isotopes (RIB linac) which must produce high-quality beams of radioactive ions over the full mass range, including uranium, at energies above the Coulomb barrier, and have high transmission and efficiency. The latter requires the RIB linac to accept at injection ions in the 1+ charge state. A concept for such a post accelerator suitable for ions up to mass 132 has been previously described [1] . This paper presents a modified concept which extends the mass range to uranium. A high resolution separator for purifying beams at the isobaric level precedes the RIB linac. The mass filtering process will provide high purity beams while preserving transmission. For most cases a resolution of about m/ Δ m=20 000 is adequate at mass A=100 to obtain a separation between isobars of mass excess difference of 5 MeV. The design for a device capable of purifying beams at the isobaric level includes calculations up to fifth order. The RIB linac will utilize existing superconducting heavy-ion linac technology for all but a small portion of the accelerator system. The exceptional piece, a very-low-charge-state injector section needed for just the first few MV of the RIB accelerator, consists of a pre-buncher followed by several sections of cw, normally-conducting RFQ. Two stages of charge stripping are provided: helium gas stripping at energies of a few keV/u, and additional foil stripping at ∼680 keV/u for the heavier ions. In extending the mass range to uranium, however, for best efficiency the helium gas stripping must be performed at different energies for different mass ions. We present numerical simulations of the beam dynamics of a design for the complete RIB linac which provides for several stripping options and uses cost-effective solenoid focusing elements in the drift-tube linac.

The driver linac of the proposed rare isotope accelerator facility is designed to deliver 2×10 13 uranium ions per second at 400 MeV/u on target for radionuclide production via the fission and fragmentation mechanisms. The ion optics of the large acceptance, high-resolution fragment separators that follow the production target require primary beam spot widths of 1 mm. To cope with the resulting high power densities, windowless liquid lithium targets are being developed. The present designs build on existing experience with liquid lithium and liquid sodium systems that have been used for fusion and fission applications. However, no completely windowless systems have been developed or tested to date. For the beam power indicated above (400 kW), the flow requirements are up to about 20 m/s and 10 l/s linear and volume flow rates, respectively. The required target thickness is 1–1.5 g/cm 2 (2–3 cm lithium thickness). At this time a prototype windowless system with a lithium thickness of 1–2 cm is under construction. The prototype will be operated initially without beam in the Argonne liquid lithium test facility. The details of the design of the prototype and a progress report on its construction and testing will be presented.

As a first step towards developing liquid lithium target technology for a future high-power nuclear physics fragmentation facility, an adjustable thickness Li/Be hybrid target is being constructed for use at the NSCL. This target will use beryllium windows with flowing lithium. The lithium serves as a part of the target as well as the coolant. Up to 1 kW of beam power is dissipated in the target and is carried away by the recirculating liquid lithium loop. It is designed for high power beams in the mass range from oxygen to calcium. Tapered beryllium windows combined with a uniform thickness lithium channel gives an overall target thickness ranging from 0.7 to 3 g/cm2, which is adjusted by moving the target vertically. The target system design is complete and is described in this paper.

A detailed model for simulating release curves from ISOL targets has been developed. The full 3D geometry is implemented using Geant-4. Produced particles are followed individually from production to release. The delay time is computed event by event. All processes involved: diffusion, effusion and decay are included to obtain the overall release curve. By fitting to the experimental data, important parameters of the release process (diffusion coefficient, sticking time, …) are extracted. They can be used to improve the efficiency of existing targets and design new ones more suitable to produce beams of rare isotopes.

Yields for a broad range of radioactive nuclei produced by spallation reactions, neutron-induced fission, in-flight projectile fragmentation and in-flight fission have been calculated for beams of stable nuclei at energies of 100– 1000 MeV /u . Calculations of cross-sections and yields, attenuation effects due to absorption, production from secondary reactions, and transport efficiencies for mass selection are discussed. Rare isotope yields as functions of bombarding energies for both reaccelerated and directly produced fast-fragmentation beams are presented. This information provides a foundation for a cost-effective design of a next generation rare isotope accelerator.

A method has been developed to calculate accurate high-order ion-optical maps for electrostatic and radio-frequency accelerating elements. The method has been incorporated into the arbitrary-order map-based beam optics code COSY Infinity. The treatment is restricted to the case of negligible magnetic fields, as is typical of heavy-ion accelerating cavities, and does not include space charge. For validation purposes, the beam dynamics calculated for these elements is compared against ray tracing for typical beam and cavity parameters. Different from the ray-tracing approach, parameter changes of individual components typically require only recalculation of the maps of the particular components and not the entire system, and thus the method is particularly suitable for optimization. The approach developed for accurate analytical representation of the on- and off-axis electric fields of cylindrically symmetric electrostatic lenses and radio-frequency cavities is described. Some of the many possible applications for using accurate high-order map representations of Einzel lenses, electrostatic accelerating gaps, and radio-frequency accelerating structures are discussed.

The results are presented for an experiment that compares the difference between a one- and two-step reaction setup using 1 GeV protons. The rates of production from an on-line isotope separator target containing UCx are measured for isotopes in the neutron mass region of Rb and Cs. Some details about the measured results and predictions by the Monte Carlo models are discussed. The effects of the delayed release on the extracted efficiency are generalized using analytical models for application to a wide range of nuclear decay lifetimes.

Advanced exotic beam facilities that are currently being developed will use powerful driver accelerators for the production of short-lived rare isotopes. Multi-beam drivers capable of producing high power beams from very light to very heavy ions are now technically feasible. A challenge for such facilities is the development of production targets to be used for a variety of reaction mechanisms with beam powers of about 100 kW. This paper presents engineering concepts that have been developed recently for using liquid lithium coolant for two types of targets, one for use with light-ion beams on high atomic number ( Z ) targets and the other for heavy-ion beams on low- Z targets.

There are several nuclear physics laboratories in North America that have on-going research using energetic and stopped radioactive beams. These include the large ISOL-type programs ISAC at TRIUMF and HRIBF at Oak Ridge and the in-flight fragmentation program at the NSCL of Michigan State University. There are also smaller, more specialized, programs using a variety of techniques at the 88-inch cyclotron of Berkeley, ATLAS at Argonne, the Cyclotron Institute of Texas A&M University, the Nuclear Structure Laboratory at Notre Dame University, and the Nuclear Structure Laboratory at SUNY/Stony Brook. There are also three projects on the horizon in North America for new capabilities in both the near term and more distant future. The intensities of the in-flight fragment beams at the NSCL will be increased dramatically very soon as the Coupled Cyclotron Project will be completed and commissioned for research by mid-2001. A new project, ISAC-II, has been approved in Canada. For the longer term, the United States is considering construction of a major new facility, the Rare Isotope Accelerator (RIA), which would have a very high-intensity heavy-ion driver linac. The RIA facility is proposed to utilize both ISOL and in-flight production mechanisms.

A new eXtreme MATerial (XMAT) research facility is being proposed at Argonne National Laboratory to enable rapid in situ mesoscale bulk analysis of ion radiation damage in advanced materials and nuclear fuels. This facility combines a new heavy-ion accelerator with the existing high-energy X-ray analysis capability of the Argonne Advanced Photon Source. The heavy-ion accelerator and target complex will enable experimenters to emulate the environment of a nuclear reactor making possible the study of fission fragment damage in materials. Material scientists will be able to use the measured material parameters to validate computer simulation codes and extrapolate the response of the material in a nuclear reactor environment. Utilizing a new heavy-ion accelerator will provide the appropriate energies and intensities to study these effects with beam intensities which allow experiments to run over hours or days instead of years. The XMAT facility will use a CW heavy-ion accelerator capable of providing beams of any stable isotope with adjustable energy up to 1.2 MeV/u for 238U50+ and 1.7 MeV for protons. This energy is crucial to the design since it well mimics fission fragments that provide the major portion of the damage in nuclear fuels. The energy also allows damage to be created far from the surface of the material allowing bulk radiation damage effects to be investigated. The XMAT ion linac includes an electron cyclotron resonance ion source, a normal-conducting radio-frequency quadrupole and four normal-conducting multi-gap quarter-wave resonators operating at 60.625 MHz. This paper presents the 3D multi-physics design and analysis of the accelerating structures and beam dynamics studies of the linac.

The possibility of simultaneously accelerating particles with a range of charge-to-mass ratios ( approximately 20%) to the same energy is proposed and demonstrated for a superconducting linac. Uranium ions stripped in a foil with eight charge states have been accelerated through a portion of the ATLAS linac from 286 to 690 MeV, with 94% of the injected uranium in the accelerated beam. Emittance of the resultant beam has been measured and the energy spread was 1.3% compared to 0.4% for a single charge state. This development has immediate application to the high-intensity acceleration of heavy ions that are limited by ion-source intensities, such as the proposed Rare Isotope Accelerator Facility.

A technique for producing a high-quality radioactive 56 Ni (T 1/2 =6.1 d ) beam via the two-accelerator method has been developed. Beam intensities of 2×107 56Ni/s were extracted from the ion source and 2×104 56Ni/s were delivered to the target. For a study of neutron transfer reactions in inverse kinematics, a high-efficiency detection system was built consisting of a large solid angle (2.8 sr), high-granularity Si detector array for measuring the outgoing protons in coincidence with the heavy reaction products identified with respect to mass A and nuclear charge Z in the focal plane of a recoil mass separator.

Cross sections for the 44Ti(alpha,p)47V reaction which significantly affects the yield of 44Ti in supernovae were measured in the energy range 5.7 MeV

Reactions with a heavy projectile incident on a light target can be used for the efficient in-flight production of secondary radioactive beams. An overview of this technique is given using data on 17F beams produced via the p(17O, 17F)n and d(16O, 17F)n reactions. With primary 16,17O beam currents of 100 pnA, intensities of up to 2×106 17F/s on target were achieved. Using this beam, the p(17F, α) 14O reaction was measured.

A method has been developed that can provide beams of many short-lived nuclei of interest in nucleosynthesis along the rp process path. With a {sup 17}F beam (T{sub 1/2}=64 s ) the excitation function of the {sup 17}F( p,thinsp{alpha}){sup 14} O reaction was measured to determine properties of excited states in {sup 18}Ne . These states influence the rate of the {sup 14}O( {alpha},thinspp){sup 17} F reaction which is important for understanding energy generation and nucleosynthesis in x-ray bursts. The present direct measurements yield a pattern of resonances and cross sections which differ substantially from previous estimates. {copyright} {ital 1999} {ital The American Physical Society}