IIT, Chicago, Illinois, USA
ANL, Argonne, USA
Soreq NRC, Yavne, Israel
The Argonne Tandem Linac Accelerator System (ATLAS) is the only national user facility for low-energy stable heavy ion beams. With the recent commissioning of the Californium Rare Isotope Breeder Upgrade (CARIBU), ATLAS will also be used to accelerate radioactive beams. We here propose to convert ATLAS into a multi-user facility by simultaneously accelerating stable beams from the ECR ion source and radioactive beams from an Electron Beam Ion Source (EBIS) charge breeder under development for CARIBU. Radioactive beams produced from EBIS will contain several charge states of the same isotope, and could be injected into ATLAS in short (~10 μs) pulses. We propose modifications of the existing ATLAS low energy beam transport line that will enable the simultaneous injection and acceleration of one or more charge states from EBIS and a stable ion beam from the ECR. Beam dynamics simulations using the code TRACK confirmed the feasibility of these modifications. The realization of this concept will increase the available beam time, the intensity of radioactive beams and improve the quality of the delivered beams as well.
ANL, Argonne, USA
A new inflight radioactive ion separator (AIRIS) is being designed for the ATLAS facility at Argonne. AIRIS will be used to separate and produce secondary radioactive beams from the interaction of ATLAS primary beams in a production target. AIRIS will be at least 10 times more efficient than the existing radioactive beam capability. We have made significant progress in the design and simulations of AIRIS including full 3D models of all the elements to consider their real dimensions and produce realistic 3D fields. The resolving power of the device has been studied for several reaction cases using realistic cross sections and kinematics. In addition to the magnetic separation of the device, a RF sweeper is being designed to take advantage of the time separation of the different beams and reject the primary beam tail and other potential contaminants in order to produce higher purity secondary beams. The latest AIRIS design and simulation results will be presented and discussed.
Fermilab, Batavia, USA
LBNL, Berkeley, California, USA
BARC, Mumbai, India
ANL, Argonne, USA
ANL, Argonne, USA
The ATLAS National User Facility is world’s first CW superconducting linac and provides variety of ion beams for nuclear physics experiments for the past 30 years. The accelerator is being continuously upgraded to extend the scientific reach. A new normal conducting CW RFQ capable to provide total voltage up to 2.1 MV for the heaviest uranium ions has been added in the front of the SC linac in order to increase efficiency and intensity of both stable and radioactive ion beams. The RFQ has been fully integrated into the ATLAS and it is routinely operated since January 2013. A new cryomodule of high-performance 72.75 MHz SC QWRs has been built and currently it is being commissioned off-line. New design and fabrication techniques have been applied for production of QWRs which resulted to new record voltages up to 4-5 MV per cavity and low residual resistance of 2-3 nOhm at 2K as was demonstrated in individual cold testing of several QWRs. Primary purpose of the new cryomodule is to increase intensity of accelerated stable ion beams. Beam commissioning will take place at the end of year after substantial modification of the booster area including radiation shielding.
ANL, Argonne, USA
Cryomagnetics, Inc., Tennessee, USA
Proton and heavy-ion linacs with superconducting cavities require compact lattices to suppress emittance growth in the low-velocity region. For beam focusing superconducting solenoids are superior in this regard to normal conducting quadrupoles. A superconducting solenoid with integral x-y steering coils has been fabricated for the Project-X Injector Experiment (PXIE) half-wave resonator cryomodule. It is capable of generating 6 T solenoidal fields and dipole steering fields of 30 T•mm field integrals in both of transverse directions. We experimentally investigated issues for practical use of this solenoid in cryomodules including: 1) the superposition of dipole steering fields on solenoidal fields, 2) the magnetic axis of the solenoid with respect to the mechanical references in cryogenic temperatures, and 3) the residual magnetic field generated by the solenoid on the superconducting RF cavity surfaces even after degaussing; a 72 MHz quarter wave resonator was used for this experiment. In this paper, we present details of experimental setup and results.
ANL, Argonne, USA
We have recently designed a 176 MHz CW RFQ for the SARAF upgrade project. A full 3D model of the structure including vane modulation was developed. The design was heavily optimized using large scale electromagnetic simulations. Following the choice of the vane type and geometry, the shape and dimensions of the undercuts were optimized to produce a flat field along the structure. Simulations of the same structure with different lengths were performed to verify that the design length produced the best separation of the operating mode from neighbouring modes. If built as designed the RFQ should not need dipole rods for mode separation, but their effect were studied in the case of manufacturing errors. Finally, the tuners were designed and optimized to tune the main mode without affecting the field flatness. The design optimization was mainly performed using CST Micro-Wave Studio and the results were verified using both HFSS and ANSYS. The results of these studies will be presented and discussed.