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Actinium-225 and 213Bi have been used successfully in targeted alpha therapy (TAT) in preclinical and clinical research. This paper is a continuation of research activities aiming to expand the availability of 225Ac. The high-energy proton spallation reaction on natural thorium metal targets has been utilized to produce millicurie quantities of 225Ac. The results of sixteen irradiation experiments of thorium metal at beam energies between 78 and 192 MeV are summarized in this work. Irradiations have been conducted at Brookhaven National Laboratory (BNL) and Los Alamos National Laboratory (LANL), while target dissolution and processing was carried out at Oak Ridge National Laboratory (ORNL). Excitation functions for actinium and thorium isotopes, as well as for some of the fission products, are presented. The cross sections for production of 225Ac range from 3.6 to 16.7 mb in the incident proton energy range of 78–192 MeV. Based on these data, production of curie quantities of 225Ac is possible by irradiating a 5.0 g cm−2 232Th target for 10 days in either BNL or LANL proton irradiation facilities.

Electroplated depositions of Sm were prepared using a vertical well-type electrodeposition unit with an aqueous ammonium acetate electrolyte system, with an average deposition yield just over 87%. The depositions were analyzed for morphology and thickness by scanning electron microscopy (SEM) and chemical composition by energy dispersion X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) before and after firing. The depositions were fired at 125–700 °C, while varying the heating rate from 0.5 to 10 °C/min in either an oxidizing or reducing atmosphere. A heating rate of 10 °C/min was slow enough to prevent disruption of the deposition morphology during firing. A gas sweep enhanced the removal of any organic substituents, with an oxidizing environment being more advantageous than a reducing environment.

Multi-step resonance laser ionization has become an essential tool for the production of isobarically pure radioactive ion beams at the isotope separator on-line (ISOL) facilities around the world. A resonant ionization laser ion source (RILIS) has been developed for the former Holifield Radioactive Ion Beam Facility (HRIBF) of Oak Ridge National Laboratory. The RILIS employs a hot-cavity ion source and a laser system featuring three grating-tuned and individually pumped Ti:Sapphire lasers, especially designed for stable and simple operation. The RILIS has been installed at the second ISOL production platform of former HRIBF and has successfully provided beams of exotic neutron-rich Ga isotopes for beta decay studies. This paper reports the features, advantages, limitations, and on-line and off-line performance of the RILIS.

Samarium thin-films doped with a 252 Cf radiotracer were used to study the effects of annealing on the release of fission fragments from electrodeposited films. An ammonium acetate molecular plating technique was utilized to perform the depositions. The fission fragment yields were measured using a unique technique involving the exposure of aluminum foils to the deposited material for a fixed time followed by gamma-ray spectroscopy to determine the rate at which the fission fragments implanted into the foils. Annealing of the electrodeposited films was found to have no effect on the release of fission fragments.

We present results and discuss the use of aluminum nitride as a promising source material for Accelerator Mass Spectrometry (AMS) and Radioactive Ion Beams (RIBs) science applications of 26Al isotopes. The measurement of 26Al in geological samples by AMS is typically conducted on Al2O3 targets. However, Al2O3 is not an ideal source material because it does not form a prolific beam of Al− required for measuring low-levels of 26Al. Multiple samples of aluminum oxide (Al2O3), aluminum nitride (AlN), mixed Al2O3–AlN as well as aluminum fluoride (AlF3) were tested and compared using the ion source test facility and the stable ion beam (SIB) injector platform at the 25-MV tandem electrostatic accelerator at Oak Ridge National Laboratory. Negative ion currents of atomic and molecular aluminum were examined for each source material. It was found that pure AlN targets produced substantially higher beam currents than the other materials and that there was some dependence on the exposure of AlN to air. The applicability of using AlN as a source material for geological samples was explored by preparing quartz samples as Al2O3 and converting them to AlN using a carbothermal reduction technique, which involved reducing the Al2O3 with graphite powder at 1600 °C within a nitrogen atmosphere. The quartz material was successfully converted to AlN. Thus far, AlN proves to be a promising source material and could lead towards increasing the sensitivity of low-level 26Al AMS measurements. The potential of using AlN as a source material for nuclear physics is also very promising by placing 26AlN directly into a source to produce more intense radioactive beams of 26Al.

The planned rare isotope accelerator facility RIA in the US would become the most powerful radioactive beam facility in the world. RIA's driver accelerator will be a device capable of providing beams from protons to uranium at energies of at least 400 MeV per nucleon, with beam power up to 400 kW. Radioactive beam production relies on both the in-flight separation of fast beam fragments and on the ISOL technique. In both cases the high beam power poses major challenges for target technology and handling and on the design of the beam production areas. This paper will give a brief overview of RIA and discuss aspects of ongoing conceptual design work for the RIA target areas.

A technique for measuring mass differences has been developed at the Holifield Radioactive Ion Beam Facility (HRIBF) that requires no specialized equipment. Mass differences are measured as position differences between known and unknown-mass isobars, dispersed at the image of the energy-analyzing magnet following the 25 MV tandem post-accelerator, and identified by an energy-loss measurement. The technique has been demonstrated on neutron-rich 77–79Cu and 83–86Ge isotopes produced using the isotope separator online (ISOL) method with the 238U(p,fission) reaction, where a mass accuracy of 500 keV was achieved. These nuclides are well suited to the measurement technique, as they readily migrate out of the production target and to the ion source and comprise the most neutron-rich elements of the isobarically mixed beam. Because modest precision mass values can be obtained with only a few tens of counts of the nuclide of interest among orders of magnitude more of the isobaric neighbors closer to stability, the sensitivity of this technique makes it appropriate for initial mass measurements far from stability.

A variety of ISOL targets for generation of radioactive ion beams have been successfully developed at the Holifield Radioactive Ion Beam Facility. Short-lived ion species generated from fast release targets made up of fibrous materials such as HfO2, and coated low-density carbon foam target matrices such as UC2/RVCF targets have been applied in important research programs of nuclear physics and astrophysics. In this paper, computer modeling of the HRIBF targets are introduced, and the computation results are coincident with the experimental measurements. These studies provide a cost effective method to understand beam power deposition as well as temperature distribution in ISOL target presently utilized at the HRIBF and predict the capability of high power ISOL target designs and the temperature profiles with other target materials and geometries for the future facility upgrade.

A new infiltration coating method has been conceived for uniform and controlled thickness deposition of target materials onto highly permeable, complex-structure matrices to form short-diffusion-length isotope-separator-on-line (ISOL) production targets for radioactive ion beam research applications. In this report, the infiltration technique is described in detail and the universal character of the technique illustrated in the form of SEMs of several metal-carbide, metal-oxide and metal-sulfide targets for potential use at present or future radioactive ion beam research facilities.

Neutron-rich radioactive ion beams available from the HRIBF allow a variety of measurements around the 132Sn region, including Coulomb excitation, fusion-evaporation, and neutron transfer. The B ( E 2 ; 0 + → 2 + ) value for first 2+ excited states of even-even neutron-rich 132–136Te and 126–134Sn have been measured by Coulomb excitation in inverse kinematics. The results are discussed in terms of the shell model and the quasiparticle random phase approximation. Neutron transfer onto a 134Te beam, from 9Be and 13C targets to populate single-particle states in 135Te, has also been studied. Gamma rays from the 13C(134Te, 12C) reaction were used to identify the ν i 13 / 2 state in 135Te, at an energy of 2109 keV. These and other results, and plans for future experiments with these neutron-rich beams, are presented.

Neutron-rich radioactive ion beams available from the HRIBF allow a variety of exciting measurements around the 132 Sn region, including Coulomb excitation, fusion-evaporation, and neutron transfer. The B ( E 2 ; 0 + → 2 + ) value for first 2 + excited states of neutron-rich 132,134,136 Te and 126,128,130,132,134 Sn have been measured by Coulomb excitation in inverse kinematics. The results are discussed in terms of the shell model and the quasiparticle random phase approximation. Neutron transfer onto a 134 Te beam, from 9 Be and 13 C targets to populate single-particle states in 135 Te, has also been studied. Results, and plans for future experiments with these neutron-rich beams, are presented.

Radioactive Ion Beams (RIBs) at the Holifield Radioactive Ion Beam Facility (HRIBF) are produced using the isotope separation on-line technique and are subsequently accelerated up to a few MeV per nucleon for use in nuclear physics experiments. The first RIB experiments at the HRIBF were completed at the end of 1998 using 17F beams. Since then other proton-rich ion beams have been developed and a large number of neutron-rich ion beams are now available. The neutron-rich radioactive nuclei are produced via proton-induced fission of uranium in a low-density matrix of uranium carbide. Recently developed RIBs include 25Al from a silicon carbide target and isobarically pure beams of neutron-rich Ge, Sn, Br and I isotopes from a uranium carbide target.

The evolution of the giant dipole resonance (GDR) in 120 Sn and 208 Pb nuclei at excitation energies in the range of 30–130 MeV and 40–110 MeV, respectively, were studied by measuring high energy γ rays from the decay of the resonance. The excited states were populated by inelastic scattering of α particles at beam energies of 40 and 50 MeV/nucleon for 120 Sn and 40 MeV/nucleon for 208 Pb. A systematic increase of the resonance width with increasing excitation energy was observed for both nuclei. The observed width evolution was compared to calculations employing a model that adiabatically couples the collective excitation to the nuclear shape, and to a model based on the collisional damping of nucleons. The adiabatic coupling model described the width evolution in both nuclei well, whereas the collisional damping calculation could describe the width evolution only in 208 Pb. Light-particle inelastic scattering populates low angular momentum states in the target nucleus. The observed width increase is therefore interpreted to be predominantly due to fluctuations in the nuclear shape induced by temperature. This interpretation is consistent with the adiabatic model calculations and with recent angular momentum-gated measurements of the GDR in excited Sn isotopes.

The recently discovered superdeformed band in one of the strontium isotopes has been identified as belonging to 83Sr from a study with the Gammasphere array and the Microball charged-particle detector system. From its decay pattern, a spin of (81 ± 2) 2 h is deduced for the highest level of this band. Evidence for very fast transition rates and agreement of the characteristics of this band with the theoretical predictions establish the yrast superdeformed nature of this band in 83Sr.