In the last two decades, numerical and experimental studies have extensively explored the impact of the space charge on bunched beams in both linear accelerators and storage rings. However, fully accounting for space charge effects over the entire accelerator is computationally intensive, especially in storage rings, where simulations must track beam dynamics over many turns and extended time periods. In many cases, space charge forces cannot be neglected, motivating the development of an alternative computational model. Here, we explore space charge-induced nonlinear dynamics using a model that approximates the Coulomb force by concentrating its effects at discrete locations along the accelerator. This approach enables efficient analyses of the full six-dimensional phase space evolution under space charge effects. Future work will apply this model to further investigate the interplay between space charge and beam-beam interactions in colliders, as well as to assess long-term stability criteria in ring accelerators.

JuTrack is a Julia-based accelerator modeling and tracking package that utilizes compiler-level automatic differentiation (AD) to enable fast and accurate derivative calculations. While JuTrack provides a solid foundation for beam dynamics simulations, its capabilities must be extended to support the Facility for Rare Isotopes (FRIB) linac. This includes modeling heavy-ion linac accelerator components such as the liquid-lithium charge stripper, which facilitates efficient acceleration by remove electrons from heavy isotopes, and incorporating multi-charge state acceleration tracking, which allows for charge-dependent beam dynamics. These extensions address challenges such as the beam matching and optimization of multi charge state through various accelerating structures and beam-material interaction modeling while maintaining the auto differentiation capability. This work focuses on adapting JuTrack to incorporate these elements, enhancing its online modeling abilities. We present modifications to JuTrack’s framework and demonstrate their performance in FRIB simulations.

We use one-dimensional measurements to reconstruct the four-dimensional phase space of an ion beam at the Argonne Tandem Linac Accelerator System (ATLAS) using maximum entropy tomography. This was accomplished with a novel algorithm that directly reconstructs 4D from 1D. The results were compared against a quadrupole scan measurement of the phase space. Finally, an error analysis method employing statistical analysis was used to estimate the errors.

During the first three years since May 2022, FRIB has been operating safely meeting expectations of both scientific and industrial users with high machine availability, while ramping up the beam power to 20 kW for heavy ions including uranium. The paper summarizes the operational experience and challenges, accelerator improvement projects, expansions in user stations, accelerator R&D and workforce growth programs, and preparation for facility upgrades*.

In the last two decades, numerical and experimental studies have extensively explored the impact of the space charge on bunched beams in both linear accelerators and storage rings. However, fully accounting for space charge effects over the entire accelerator is computationally intensive, especially in storage rings, where simulations must track beam dynamics over many turns and extended time periods. In many cases, space charge forces cannot be neglected, motivating the development of an alternative computational model. Here, we explore space charge-induced nonlinear dynamics using a model that approximates the Coulomb force by concentrating its effects at discrete locations along the accelerator. This approach enables efficient analyses of the full six-dimensional phase space evolution under space charge effects. Future work will apply this model to further investigate the interplay between space charge and beam-beam interactions in colliders, as well as to assess long-term stability criteria in ring accelerators.

JuTrack is a Julia-based accelerator modeling and tracking package that utilizes compiler-level automatic differentiation (AD) to enable fast and accurate derivative calculations. While JuTrack provides a solid foundation for beam dynamics simulations, its capabilities must be extended to support the Facility for Rare Isotopes (FRIB) linac. This includes modeling heavy-ion linac accelerator components such as the liquid-lithium charge stripper, which facilitates efficient acceleration by remove electrons from heavy isotopes, and incorporating multi-charge state acceleration tracking, which allows for charge-dependent beam dynamics. These extensions address challenges such as the beam matching and optimization of multi charge state through various accelerating structures and beam-material interaction modeling while maintaining the auto differentiation capability. This work focuses on adapting JuTrack to incorporate these elements, enhancing its online modeling abilities. We present modifications to JuTrack’s framework and demonstrate their performance in FRIB simulations.

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.

We use one-dimensional measurements to reconstruct the four-dimensional phase space of an ion beam at the Argonne Tandem Linac Accelerator System (ATLAS) using maximum entropy tomography. This was accomplished with a novel algorithm that directly reconstructs 4D from 1D. The results were compared against a quadrupole scan measurement of the phase space. Finally, an error analysis method employing statistical analysis was used to estimate the errors.