Progress in Multi-Step Abrasion Reactions Study*

A primary goal of rare isotope beam facilities is to investigate unstable isotopes that are far from stability, characterized by extreme proton-to-neutron ratios and short lifetimes. The production of these isotopes occurs with very low probability, a challenge mitigated by the high power of accelerators. Recent experimental results indicate that a multi-step reaction scheme can effectively explore the neutron-rich region. Multistep reaction contributions have been observed with the discovery of new isotopes at FRIB [1], achieved through the interaction of a ¹⁹⁸Pt beam with a 3.54 mm carbon target at an energy of 186 MeV/u. These results are compared to NSCL findings, where a ¹⁹⁸Pt beam at 85 MeV/u interacted with a thin Be target [2]. This study is being analyzed using the updated LISE⁺⁺ package framework [3], which now incorporates the Abrasion-Ablation model as a secondary step. Additionally, a new utility, “Multistep Reaction Kinematics,” has been developed to optimize fragment-separator tuning for maximum rare isotope production, taking multi-step reactions into account. These results will be presented, alongside discussions on the perspectives of using the Abrasion-Ablation model for multi-step reactions in the fission case.

1. O.B. Tarasov et al., PRL 132, 072501 (2024).

2. K. Haak et al., PRC 108, 034608 (2023).

3. O. B. Tarasov and D. Bazin, Nucl. Instrum. Methods Phys.Res., Sect. B 266, 4657 (2008); http://lise.nscl.msu.edu.