High-power superconducting ion linear accelerators play a vital role in both scientific research and industrial applications. However, their RF usage efficiency remains relatively low. In this paper, we review two innovative concepts: recirculating ion linear accelerators and energy recovery ion linear accelerators. These approaches significantly improve RF efficiency by enabling the ion beam to traverse the same superconducting cavity multiple times and by recovering the energy of the accelerated ion beam to return it to the RF cavities. We also propose a demonstrator for the recirculating ion linear accelerator using a scaled, low-energy electron accelerator, and discuss the potential application of the energy recovery ion accelerator in a full energy recovery electron-ion collider. These concepts offer promising avenues to substantially reduce both the construction and operational costs of superconducting linear accelerators.

High-power proton/ion linear accelerators have important applications in both scientific research and industry. However, operation of such accelerators with megawatt-level beam power is expensive and limits the broad availability of those facilities. In this study, we propose a novel energy recovery ion linear accelerator in which the final high-energy GeV-level ion beam is reused to give its energy back to the RF fields in the accelerator. This substantially reduces the power consumption of the linear accelerator and also avoids the need for a high-power beam dump.

JuTrack is a novel accelerator modeling and tracking package developed in the Julia programming language. Taking advantage of compiler-level automatic differentiation (AD), JuTrack allows rapid and accurate derivative calculations for arbitrary differentiable functions. This paper introduces the core capabilities of JuTrack, including lattice modeling and particle tracking, and demonstrates how AD-derived derivatives enhance the efficiency of beam physics studies through several practical examples.