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

Abstract

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.

Superconducting Solenoid Lens for a High Energy Part of a Proton Linac Front End

“…Early modeling studies showed that the most dangerous case is for a high current quench in a BC, where all of the solenoid's stored energy may be dissipated in a small volume wound with narrow (0.5 mm round) strand. The early quench development model [11] and test results [8] demonstrated that the SS1 was relatively safe when using a single optimized dump resistor across the power leads for energy extraction.…”

“…Reference [2] contains an overview of the design constraints and solenoid R&D challenges. Progress in developing these lenses has previously been reported for the CH and SS1 solenoids [3][4][5][6][7][8]. In this paper we discuss the design and performance of a model SS2 solenoid and make detailed comparisons of the magnet quench performance to predictions of a model used to study quench development and protection.…”

Certification of Superconducting Solenoid-Based Focusing Lenses

“…The design and performance of solenoids for the SS1 and SS2 sections is presented in a separate report [2]. This paper relates to the CH-section solenoids, which require the use of a cryostat to provide the necessary cooling conditions for the superconducting lens.…”