Optical matrix optimization for the study of unbound nuclei

In order to study neutron-rich nuclei, the MoNA Collaboration at the Facility for Rare Isotope Beams employs the invariant mass technique that uses the conservation of momentum and energy of the decay products. The particle kinematics are reconstructed from the MoNA-LISA array for the neutrons and the charged detector suite (tracking chamber, ionization chamber and timing scintillator) for the charged particles. An optical transfer matrix representing the Sweeper magnetic field allows reconstructing the position, angle and momentum of the charged particles from the sweeper detectors to the scattering vertex within the target. the We estimated this matrix using an algorithm coded in Python and the primary beams taken from the MoNA experimental campaign in June 2025. Its accuracy was then verified through the predicted kinematic variables of the contaminants. One key feature of our algorithm is to also tune the matrix elements to optimize the reconstructed quantities providing a more accurate estimation of the state of the particles at the production target. The status of this research will be presented and discussed.