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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.

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.

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.

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 (

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

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.

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.

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.

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.

A Viewpoint on: Production cross sections from 82 Se fragmentation as indications of shell effects in neutron-rich isotopes close to the drip-line O. B. Tarasov, M. Portillo, D. J. Morrissey, A. M. Amthor, L. Bandura, T. Baumann, D. Bazin, J. S. Berryman, B. A. Brown, G. Chubarian, N. Fukuda, A. Gade, T. N. Ginter, M. Hausmann, N. Inabe, T. Kubo, J. Pereira, B. M. Sherrill, A. Stolz, C. Sumithrarachichi, M. Thoennessen, and D. Weisshaar Phys. Rev. C 87, 054612 (2013) – Published May 20, 2013

The Argonne Tandem Linear Accelerator System (ATLAS) has been operating on a 24 hour, seven days a week schedule since the beginning of Fiscal Year 1994. Twenty-six different ion species ran during this period in 71 separate experiments. During the past year, there have been many projects undertaken to improve operation efficiency and upgrade various accelerator systems. There is also a new ECR ion source construction project underway. This paper covers, linac operation and new tuning techniques, the second generation ECR source construction project, the refrigerator system upgrade, an upgrade to the control system. Also described is a future expansion of ATLAS as an Exotic Beam Facility. (ATLAS is a world class heavy ion accelerator with an estimated value of approximately $80 million.) A concept that would utilize ATLAS as the foundation for a facility to generate and accelerate radioactive beams is briefly discussed.

The fringing fields of magnets with large apertures and short lengths greatly affect ion-optical calculations. In particular, for a high magnetic field where the iron core becomes saturated, the effective lengths and shapes of the field distribution must be considered because they change with the excitation current. Precise measurement of the three-dimensional magnetic fields and the correct application of parameters in the ion-optical calculations are necessary. First we present a practical numerical method of extracting full 3D magnetic field maps of magnetic multipoles from 2D field measurements of the surface of a cylinder. Using this novel method, we extracted the distributions along the beam axis for the coefficient of the first-order quadrupole component, which is the leading term of the quadrupole components in the multipole expansion of magnetic fields and proportional to the distance from the axis. Higher order components of the 3D magnetic field can be extracted from the leading term via recursion relations. The measurements were done for many excitation current values for the large-aperture superconducting triplet quadrupole magnets (STQs) in the BigRIPS fragment separator at the RIKEN Nishina Center RI Beam Factory. These distributions were parameterized using the Enge functions to fit the fringe field shapes at all excitation current values, so that unmeasured values are interpolated. The extracted distributions depend only on the position along the beam axis, and thus the measured three-dimensional field can easily be parameterized for ion-optical calculations. We implemented these parameters in the ion-optical calculation code COSY INFINITY and realized a first-order calculation that incorporates the effect of large and varying fringe fields more accurately. We applied the calculation to determine the excitation current settings of the STQs to realize various optics modes of BigRIPS and the effectiveness of this approach has been demonstrated.

The Super Separator Spectrometer S3 is a device designed for experiments with the very high intensity stable ion beam of the superconducting linear accelerator of the SPIRAL2 facility. Its Physics goals cover the study of radioactive ions produced by fusion-evaporation reactions, like superheavy elements or neutron deficient nuclei close to the proton drip line, but also neutron rich nuclei produced by multi-nucleon transfer reactions as well as ion-ion atomic interactions. It is composed of a two-step separator, with a momentum achromat followed by a mass spectrometer. Superconducting multipole triplets, combining quadruple, sextuple and octupole fields, allow a combination of high transmission and mass resolution. A specific open multipole has been designed to stop the high beam power at the first momentum dispersive plane. A decay spectroscopy detection set-up or a low energy branch can be coupled to S3 for a wide range of studies.

The recently completed positive-ion injector for the heavy-ion accelerator ATLAS is a replacement for the tandem injector of the present tandem-linac system. Unlike the tandem, the new injector provides ions from the full range of the periodic table. The concept for the new injector, which consists of an ECR ion source on a voltage platform coupled to a very-low-velocity superconducting linac, introduces technical problems and uncertainties that are well beyond those encountered previously for superconducting linacs. The solution to these problems and their relationship to performance are outlined, and experience in the operation of ATLAS with its new injector is discussed.

A Positive-Ion Injector (PII) designed to enable ATLAS to accelerate all stable nuclei has been completed and successfully tested. This new injector system consists of an ECR source on a 350-kV platform coupled to a 12-MV superconducting injector linac formed with four different types of independently-phased 4-gap accelerating structures. The injector linac is configured to be optimum for the acceleration of uranium ions from 0.029 to ≈ 1.1 MeV/u. When ions with q/A > 0.1 are accelerated by PII and injected into the main ATLAS linac, CW beams with energies over 6 MeV/u can be delivered to the experimental areas. Since its completion in March 1992, PII has been tested by accelerating 30 Si 7+ , 40 Ar 11+ , 132 Xe 13+ , and 208 Pb 24+ . For all of these, transmission through the injector linac was ∼100% of the pre-bunched beam, which corresponds to ∼60% of the DC beam from the source. The accelerating fields of the superconducting resonators were somewhat greater than the design goals, and the whole system ran stably for long periods of time.

A search for new isotopes using in-flight fission of a 345 MeV/nucleon 238U beam has been carried out at the RI Beam Factory at the RIKEN Nishina Center. Fission fragments were analyzed and identified by using the superconducting in-flight separator BigRIPS. We observed 45 new neutron-rich isotopes: 71Mn, 73,74Fe, 76Co, 79Ni, 81,82Cu, 84,85Zn, 87Ga, 90Ge, 95Se, 98Br, 101Kr, 103Rb, 106,107Sr, 108,109Y, 111,112Zr, 114,115Nb, 115,116,117Mo, 119,120Tc, 121,122,123,124Ru, 123,124,125,126Rh, 127,128Pd, 133Cd, 138Sn, 140Sb, 143Te, 145I, 148Xe, and 152Ba.

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.

To be published in Journal of the Physical Society of Japan; A search for new isotopes using in-flight fission of a 345 MeV/nucleon $^{238}$U beam has been carried out in the commissioning experiment of the next-generation in-flight radioactive beam separator BigRIPS at the RI beam factory at the RIKEN Nishina Center. Two neutron-rich palladium isotopes $^{125}$Pd and $^{126}$Pd were observed for the first time, which demonstrates the great potential of the RIKEN RI beam factory.

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.

A suite of nuclear and atomic physics codes for computing a variety of quantities relevant for heavy-ions over a wide energy range passing through material were implemented in the DA-based beam optics code COSY Infinity. As extensions to COSY we also developed a limited fission model, map computation for beam-material interactions, and a hybrid map-Monte-Carlo mode that allows relatively fast and accurate fragment separator design, end-to-end modeling and simulations, and performance optimization. Some results are briefly mentioned; details will be published elsewhere.

International audience; $S^3$ (Super Separator Spectrometer) is a device proposed 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 100pµA for lighter ions (A < 40 – 50) depending on the final choice of the ECR (Electron Cyclotron Resonance) ion source. These unprecedented intensities open new opportunities in several physics domains, e.g. super-heavy and very-heavy nuclei, spectroscopy at and beyond the dripline, muld-nucleon transfer and deep-inelastic reactions, isomers and ground state properties and nuclear molecular resonances. An international collaboration interested in the aforementioned physics has been formed for developing technical solutions for this new instrument.

Experiments were conducted to demonstrate the stable operation of a windowless liquid lithium target under extreme thermal loads that are equivalent to uranium beams from the proposed Rare Isotope Accelerator (RIA) driver linac. The engineering and safety issues accompanying liquid lithium systems are first discussed. The liquid metal technology knowledge base generated primarily for fast reactors, and liquid metal cooled fusion reactors, was applied to the development of these systems in a nuclear physics laboratory setting. The use of a high energy electron beam for simulating a high power uranium beam produced by the RIA driver linac is also described. Calculations were performed to obtain energy deposition profiles produced by electron beams at up to a few MeV to compare with expected uranium beam energy deposition profiles. It was concluded that an experimental simulation using a 1-MeV electron beam would be a valuable tool to assess beam-jet interaction. In the experiments, the cross section of the windowless liquid lithium target was 5 mm x 10 mm, which is a 1/3rd scale prototype target, and the velocity of the liquid lithium was varied up to 6 m/s. Thermal loads up to 20 kW within a beam spot diameter of 1mm were applied on the windowless liquid lithium target by the 1-MeV electron beam. The calculations showed that the maximum power density and total power deposited within the target, from the electron beam, was equivalent to that of a 200-kW, 400-MeV/u uranium beam. It was demonstrated that the windowless liquid lithium target flowing at velocities as low as 1.8 m/s stably operated under beam powers up to 20 kW without disruption or excessive vaporization.

A group including many ANL Physics Division staff and ATLAS outside users has discussed possibilities for research with radioactive ion beams and prepared a working paper entitled ‘‘Concept for an Advanced Exotic Beam Facility Based on ATLAS.’’ Several subgroups have been working on issues related to ion sources and targets which could be used in the production and ionization of radionuclides with high power primary beams. Present activities include: (a) setting up an ion source test stand to measure emittances and energy spreads of ISOL‐type ion sources, (b) experiments to evaluate methods of containing liquid uranium for production targets, (c) experimental evaluation of geometries for the generation of secondary neutron beams for production of radionuclides, (d) setting up an ISOL‐type ion source at a neutron generator facility to measure fission fragment release times and efficiencies, and (e) computer simulations of an electron‐beam charge‐state amplifier to increase the charge states of 1+ secondary...

Lowell Bollinger, a pioneer nuclear physics researcher and recipient of the Bonner Prize of the American Physical society, died on 25 September 2014 at the age of 91 in Harpswell, Maine. Bollinger was brought up in India, educated at Oberlin College, spent some time working at the Aircraft Engine Research Laboratory in Cleveland, and then attended Cornell University, where he received his Ph.D. in 1951. His thesis research advisor was Giuseppe Cocconi, on one of the earliest underground cosmic ray measurements, observing muons 600-m deep in a salt mine.

The Positive-Ion Injector (PII) for ATLAS is complete. First beams from the new injector have been accelerated and used for experiments at ATLAS. The POI consists of an ECR ion source on a 350-kV platform and a low-velocity superconducting linac. The first acceleration of uranium for the experimental program has demonstrated that the design goals of the project have been met, Since the summer of 1992, the new injector has been used for the research program approximately 50% of the time. Longitudinal beam quality from the new injector has been measured to be significantly better than comparable beams from the tandem injector. Changes to the mix of resonators in the main ATLAS accelerator to match better the velocity profile for heavy beams such as uranium are nearly complete and uranium energies up to 6.45 MeV per nucleon have been achieved. The operating experience of the new ATLAS facility will be discussed with emphasis on the measured beam quality as well as achieved beam energies and currents. >

A secondary beam of radioactive /sup 17/F was produced at the ATLAS accelerator and delivered to an experimental target station with an intensity of as much as 5.10/sup 5/ ions/s for use in the research program. Beams of /sup 17/F were produced via the p(/sup 17/O,/sup 17/F)n or d(/sup 16/O,/sup 17/F)n reactions by bombarding a gas-filled cell with up to 300 pnA beams of /sup 17/O or /sup 16/O from the ATLAS superconducting linac. The gas target, with HAVAR windows, was maintained at pressures as high as 500 Torr. The beam quality was dominated by small-angle scattering in the gas cell windows, by the reaction kinematics and beamline acceptance. Detailed beam parameters are presented. Plans for relocation of the target to allow improved capture efficiency and acceleration or de-acceleration of the secondary beam will also be discussed.

Numerical simulations indicate that it should be possible to use an electron beam to strip 1/sup +/ DC radioactive ion beams to 2/sup +/ or higher charge states with on the order of 40-80% efficiency. The device, which we call an electron-beam charge-state amplifier, is similar to an electron beam ion source, except that it is not pulsed, the beams are continuous. The 2/sup +/ beams are obtained in a single pass through a magnetic solenoid while higher charge states may be reached via multiple passes. An unexpected result of the ion optics simulations is that the normalized transverse emittance of the ion beam is reduced in proportion to the charge-state gain. Ion beams with realistic emittances and zero angular momentum relative to the optic axis before entering the solenoid will travel though the solenoid on helical orbits which intercept the axis once per cycle. With an ion beam about 2 mm in diameter and an electron beam about 0.2 mm in diameter, the ion stripping only occurs very near the optic axis, resulting in the emittance reduction.

A superconducting quadrupole magnet has been designed for use as the focusing element in a low charge state linac proposed at Argonne. The expected field gradient is 350 T/m at an operating current of 53 A, and the bore diameter is 3 cm. The use of rare earth material holmium for pole tips provides about 10% more gradient than iron pole tips. The design and the status of construction of a prototype singlet magnet is described.

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 with 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 presented. This paper presents a modified concept which extends the mass range to uranium. 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: He gas stripping at energies of a few keV/u, and additional foil stripping at /spl sim/600 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 beam dynamics for 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 GSI projectile fragment separator FRS has demonstrated with many pioneering experiments the research potential of in-flight separators at relativistic energies. Although the present facility has contributed much to the progress in the field of nuclear structure physics, major improvements are desirable in the future. The characteristics of the proposed next-generation facility at GSI, the Super-FRS, will be presented and compared to other projects. The Super-FRS is a large-acceptance superconducting fragment separator followed by different experimental branches including a combination with a new storage-cooler ring system. This system consists of a collector ring (CR) and a new experimental storage ring (NESR) which allow precision mass and lifetime measurements as well as in-ring reaction studies. The NESR can be operated in combination with an electron ring to measure electron scattering with exotic nuclei. This electron heavy-ion collider will open up new fields for nuclear structure research.

Various beams of short- and long-lived radioactive nuclei have recently been produced at the ATLAS accelerator at Argonne National Laboratory, using either the so-called In-Flight or the Two-Accelerator method. The production techniques, as well as recent results with 44Ti(T1/2=60y) and 17F(T1/2=64s) beams, which are of interest to nucleosynthesis in supernovae and X-ray bursts, are discussed.

The requirements of the design of beam transport systems for selecting multiple charge state beams are discussed. The layouts of two designs are presented along with the results calculated from beam transport maps.

The beam transport system at the National Superconducting Cyclotron Lab (NSCL) consists of 22 cryostats containing superconducting quadrupole doublets or triplets, and 9 superconducting dipoles. The quads achieve gradients of up to 35 T/m in the 10-cm-diameter warm bore. Operating at a maximum current of 20 A allows the helium consumption rate to be kept to less than 0.3 L/h. The dipoles produce fields in the 5-cm gap of over 1.9 T at a current of 100 A, and the two types produce bends of either +or-16 degrees or 22.5 degrees at 1.75 T for the 1.6-GeV/c heavy ion beams produced by the K1200 superconducting cyclotron. One year's operations experience demonstrates their efficiency and reliability.

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 {sup 238}U target, and (2) Fragmentation of neutron-rich heavy ion rich fission products in a secondary beams such as {sup 18}O 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, {sup 132}Sn {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.

The horizontal and vertical beam emittances and ellipse parameters are determined at the ATLAS superconducting heavy-ion linac by the well-known method of measuring the beam width at a profile monitor downstream of a quadrupole magnet as a function of the magnet current. Typically six base-to-base beam widths are measured and used in a least-squares fit to an algebraic expression for the three unknown ellipse parameters. The algorithm was derived from the first order matrix equation for the beam sigma matrix transform through the quadrupole singlet and. Drift to the profile monitor. To date the emittances of five beams from /sup 12/C/sup 4+/ to /sup 238/U/sup 26+/ have been measured at the entrance of the Positive-ion Injector Linac, yielding normalized values mostly in the range of 0.25-0.30 /spl pi/ mm-mr. These measurements will be extended systematically to several locations to identify possible sources of emittance growth and to develop more systematic beam tuning procedures.

Electron cyclotron resonance (ECR) ion source are, at present, the leading source of highly charged DC beams of positive ions. Fully stripped light ions through argon have been obtained, and ionization levels of 25-35 electrons removed have been obtained for heavy mass species. Major applications of ECR ion sources for highly charged ions now include approximately 30 nuclear, atomic, and high-energy physics laboratories worldwide. >

A prototype of the beamline switching magnets needed for operation of the National Superconducting Cyclotron Lab's 1.6 GeV/c heavy ion beam transport system has been constructed and is undergoing tests. The device features a compact design, as well as good cryogenic and magnetic efficiency. In the operational range of 1.0 to 1.75 T the required field uniformity of ± 0.1% has been obtained. The design current density in the potted coils is 17 kA/cm2at 1.75 T, and the magnet has operated at a current density of 20 kA/cm2at 1.8 T without a quench.

Doubly differential cross sections for the production of ${\ensuremath{\pi}}^{+}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}$ near the velocity of the incident beam for pion laboratory angles from 0 to 20 degrees are presented. Beams of $^{20}\mathrm{Ne}$ with $\frac{E}{A}=280, 380, \mathrm{and} 480$ MeV and $^{40}\mathrm{Ar}$ with $\frac{E}{A}=535$ MeV incident on C, NaF, KCl, Cu, and U targets were used. A sharp peak in the ${\ensuremath{\pi}}^{\ensuremath{-}}$ spectrum and a depression in the ${\ensuremath{\pi}}^{+}$ spectrum is observed at 0\ifmmode^\circ\else\textdegree\fi{} near the incident projectile velocity. The effect is explained in terms of Coulomb interactions between pions and fragments of the incident beam. Least squares fits to the data using the Coulomb correction formulas of Gyulassy and Kauffmann and an effective projectile fragment charge are made. The relationship between these data and previously measured projectile fragmentation data is discussed and a simple parametrization of projectile mass, target mass, and beam energy dependence of the differential cross sections is given.NUCLEAR REACTIONS C, NaF, Cu, U $(^{20}\mathrm{Ne},{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}})X$, $\frac{E}{A}=280\ensuremath{-}480$ MeV; C, KCl $(^{40}\mathrm{Ar},{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}})X$, $\frac{E}{A}=535$ MeV; measured $\ensuremath{\sigma}({E}_{\ensuremath{\pi}},{\ensuremath{\theta}}_{\ensuremath{\pi}})$, ${\ensuremath{\theta}}_{\ensuremath{\pi}}=0\ifmmode^\circ\else\textdegree\fi{}\ensuremath{-}20\ifmmode^\circ\else\textdegree\fi{}$, $\ensuremath{\pi}$ velocity near beam velocity; deduced projectile fragment charges, Coulomb effects.

From the scattering of 35 MeV protons from 206 Pb accurate excitation energies and angular distributions have been determined for the strongly excited collective states. These states are compared to corresponding states in 207,208 Pb. A possible explanation of the anomaly in the 5 - strength is given in terms of the core wave functions.

A system of permanent-magnet quadrupoles and dipoles is described for transporting a heavy ion beam of the Laboratory's K800 superconducting cyclotrons from the extraction system exit, through the return yoke, to the beginning of the external beamline. After a brief summary of the beam line layout, the authors discuss tests carried out on six candidate materials (Sm/sub 1/Co/sub 5/, Sm/sub 2/Co/sub 17/, NdFeB, and three types of NdFeB with various additives used to increase the coercivity) that resulted in the choice of SmCo permanent magnet material. The beam optics utilize adjustable quadrupoles and dipoles constructed from rings of permanent magnet material. To adjust the strength, the rings are rotated about the beam axis in opposite directions. Ray-tracing calculation results confirm the absence of x and y phase space mixing. >

A superconducting switching magnet capable of bending a 1.6 GeV/c beam to ±16° has been designed and is currently under construction. In the operating range of up to 1.75 T the design field uniformity is better than 0.1% in the volume occupied by the beam. The coils are wet wound with a filled epoxy and are designed to have an average current density of 17 kA/cm2when operated at the nominal maximum current of 100 A. In order to keep the liquid helium consumption low, consistent with a weekly batch-fill operation, the magnet will operate in persistant mode with small resistive coil correction magnets to provide for fine tuning of the beam.

Nuclear matter raddi were calculated from measured Coulomb energy differences and charge radii. The Coulomb energy differences were taken between nuclear states that are members of an isobaric-spin multiplet. A significant anomaly in the radius of the excess nucleons was found. In the mirror pair 41 Ca- 41 Sc, for instance, the known charge radius of the 40 Ca core was used to extract the rms radius for the 41st nucleon. This radius is virtually the same as that of the 40 Ca core, whereas any simple potential model would predict the 1f 7 2 orbit to be ∼ 20% larger than the average radius of the lower orbits. This qualitative effect is present in other mirror nuclei, and is also a feature of Coulomb energy differences from isobaric-spin analog states in heavier nuclei, for which the neutron excess is larger.

Coulomb energy differences, obtained from isobaric analog states, were made the subject of a careful quantitative study in strings of isotopes with closed proton shells. The behavior of these energies with increasing neutron excess in Ca isotopes was found to differ qualitatively from that in the Ni or Sn isotopes. With measured values of charge radii, the Coulomb energy differences are used to deduce neutron radii and nuclear matter radii. It is concluded that the addition of f 7 2 neutrons in Ca does little to change the radius of the core of closed shells in 40Ca while the addition of neutrons in Ni and Sn polarizes the core appreciably. The trend in neutron and proton radii is similar in each of the three series of isotopes.

Four-gap superconducting resonators have been developed at Argonne for use in the low-beta positive ion injector (PII) for ATLAS. These structures have been used successfully for ion velocities as low as 0.007c with q/m=0.1. First order matrix optics and linear theory for the phase space transformations in accelerating systems are applied to the PII linac which includes low-beta heavy ion RF resonators and magnetic solenoids. These provide a new method to match initial phase space ellipses when used with higher order transfer maps or ray-tracing calculations. And also we present a quantitative measure of nonlinearities using the concept of RMS emittances and deviations of phase space coordinates between linear and nonlinear transformations. As a byproduct a way of identifying the dominant source of nonlinearity of system is indicated. >