Trajectory Reconstruction in ARIS for Production Kinematics Studies

The Advanced Rare Isotope Separator (ARIS) at the Facility for Rare Isotope Beams (FRIB) is a multistage fragment separator designed to support different optical modes [1] and improve the purification of rare isotope beams. Within the LISE++ package [2], an extended configuration of ARIS was constructed in which each magnet and drift length is treated as an individual optical block. This provides a granular view of the separator, enabling a detailed analysis of the system's aggregate optics and precise trajectory reconstruction. Reconstructing particle trajectories through the system improves particle identification by enabling corrections to both magnetic rigidity (Bρ) and time of flight. In addition, we present work on global trajectory reconstruction back to the production target to enable studies of reaction kinematics [3].

[1] M. Portillo et al., "Rare-isotope production optics of ARIS preseparator", presented at HIAT’25, East Lansing, MI, USA, Jun. 2025, paper FRA02, https://meow.elettra.eu/82/pdf/FRA02.pdf.

[2] O. B. Tarasov et al., "LISEcute++, the latest generation of the LISE++ package, to simulate rare isotope production with fragment-separators", Nucl. Instrum. Methods Phys. Res. B, vol, 541, p. 4, 2023. doi/10.1016/j.nimb.2023.04.039

[3] M. Bowry et al., "Abrasion-fission reactions at intermediate energies", Phys. Rev. C, vol. 108, p. 034604, 2023. doi/10.1103/PhysRevC.108.034604