Multi-step abrasion reactions in the search for the drip line

A major objective of rare isotope beam facilities is to study isotopes far from stability with extreme proton-to-neutron ratios. Such isotopes are produced with very low probability offset by high beam power accelerator. Identification of the optimal production mechanisms is an ongoing challenge. A multi-step reaction scheme is shown to be a way to explore the neutron rich region based on experimental results [1,2]. The fact that isotopes close to the drip-lines nuclides have short half-lives, requires a fast in-flight production technique at least for the last step. Assuming Abrasion-Fission of a primary ²³⁸U beam to be a first production step to reach neutron rich nuclei in region 25 ≤ Z ≤ 70, the Initial Fissile Nucleus utility developed in the LISE⁺⁺ package can be used to generate initial cross section tables. Use of empirical parameterizations based on data with stable beams for next production steps can lead to large variations, though with the Abrasion-Ablation (AA) model use it is possible to select a mass model which better describe exotic nuclei experimental cross-sections. Difficulties and how to overcome know issues when using the AA model for the multi-step reactions will be discussed.

[1] H.Suzuki et al., Phys.Rev.C 102, 064615(2020)

[2] O.B.Tarasov et al., Phys.Rev.Lett.122, 022501(2018)