Design and Performance of Focusing Lenses for Installation Into Superconducting Cryomodules of a Proton Linac

The high energy sections of the Fermilab HINS R&D proton linac will utilize superconducting spoke resonator (SSR) RF cavities. These will be assembled into cryomodules with strong solenoid focusing lenses closely interleaved with the cavities. A design for lenses has been made for the lower (SSR1) and higher (SSR2) energy ranges of the SSR-section. Prototype lenses for both SSR1 and SSR2 sections have been built and the SSR1 has been tested. Shielding is needed to reduce the solenoid fringe field on the cavity wall below the 10 μT level, and a preliminary design was built and tested with the SSR1 prototype lens. We discuss the design requirements and challenges, and the results from quench testing and magnetic measurements of the SSR1 prototype lens.