Since starting the user operation of Facility for Rare Isotope Beams (FRIB) at Michigan State University in May 2022, the driver linac has provided more than a dozen ion beam species from Oxygen to Uranium to the production target. FRIB has routinely provided 20 kW primary beams on target since March 2025, which is a factor of 20 higher than at the beginning of scientific user operation. In this presentation, the recent progress of FRIB driver linac beam development, a discussion of efficient primary beam tuning procedures based on physics applications, and accelerator improvement projects for low-loss accelerator will be discussed.

Data inaccuracies make training an accurate Beam Quadrupole Moment at BPM (BPMQ) model challenging. Similarly, reconstructing Courant-Snyder (CS) parameters from BPMQ predictions is difficult due to BPMQ model limitations. Increasing the number of BPMQ predictions helps mitigate overfitting in CS inference caused by inaccurate BPMQ predictions. We present Bayesian Active Learning (BAL) to acquire measurements strategically, improving CS parameter inference despite model limitations.

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.

The Facility for Rare Isotope Beams (FRIB) provides rare-isotope beams for user experiments in nuclear physics, nuclear astrophysics, fundamental symmetries, etc. A superconducting driver-linac accelerates heavy-ion beams onto the production target, and the Advanced Rare Isotope Separator (ARIS) collects and purifies the rare isotope fragments of interest. Subsequently, the transfer hall beamlines deliver isotopes to user setups at experiment stations. The isotope beam condition from ARIS strongly depends on the fragment of interest. Therefore, the beamline settings are optimized for each experiment based on various users’ requirements on the fly. Two new beamlines in the transfer hall were commissioned in 2025, bringing the total number of available end stations to five. Since the first user experiments in 2022, ongoing beam tests and operations have continued to improve operational efficiency and user satisfaction. Results and findings of beam tuning obtained from the commissioning and recent operations will be reported.