PEFP low-beta SRF cavity design

An elliptical superconducting RF cavity of 700 MHz with ßg=0.42 has been designed for the Linac of Proton Engineering Frontier Project (PEFP). A double-ring stiffening structure is used for a low-beta cavity for a Lorentz force detuning. The results of the electron multipacting analysis of the cavity are presented. A HOM analysis shows that the HOM coupler's Qext is lower than 3×10
⁵
, thus reducing the influence of dangerous modes on the beam instabilities and the HOM-induced power.