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.