ANL, Argonne, Illinois, USA
IBS, Daejeon, Republic of Korea
In a collaborative effort between Argonne's Linac Development Group and the RISP project team at the Korean Institute for Basic Science, we have developed an alternative design for the pre-stripper section of the RISP driver linac. The proposed linac design takes advantage of the recent accelerator developments at Argonne, namely the ATLAS upgrades and the Fermilab PIP-II HWR Cryomodule. In particular, the state-of-the-art performance of QWRs and HWRs, the integrated steering correctors and clean BPMs for a compact cryomodule design. To simplify the design and avoid frequency transitions, we used two types of QWRs at 81.25 MHz. The QWRs were optimized for β ~ 0.05 and ~ 0.11 respectively. Nine cryomodules are required to reach the stripping energy of 18.5 MeV/u. Following the lattice design optimization, end-to-end beam dynamics simulations including all sources of machine errors were performed. The results showed that the design is tolerant to errors with no beam losses observed for nominal errors. However, the robustness of the design could be further improved by a modified RFQ design, better optimized with the multi-harmonic buncher located upstream. This could lead to a significant reduction in the longitudinal beam emittance, offering much easier beam tuning and more tolerance to errors. The proposed design and the simulation results will be presented and discussed.
WE2A04
ANL, Argonne, Illinois, USA
Cryomagnetics, Inc., Tennessee, USA
ANL, Argonne, Illinois, USA
Fermilab, Batavia, Illinois, USA
In support of Fermilab's Proton Improvement Plan-II project Argonne National Laboratory is constructing a superconducting half-wave resonator cryomodule. This cryomodule is designed to operate at 2.0 K, a first for low-velocity ion accelerators, and will accelerate ≥1 mA proton/H− beams from 2.1 to 10.3 MeV. Since 2014 the construction of 9 162.5 MHz b = 0.112 superconducting half-wave resonators, the vacuum vessel and the majority of the cryomodule subsystems have been finished. Here we will update on the status of this work and report on preliminary cavity test results. This will include cavity performance measurements where we found residual resistances of < 3 nanoOhms at low fields and peak voltage gains of 5.9 MV, which corresponds to peak surface fields of 134 MV/m and 144 mT electric and magnetic respectively.