Spin flip cross sections are also taken from the Nuclear Atlas by Bracci et al.  with differential cross sections provided by Melezhik and Wozniak . Spin flip in asymmetric collisions such as requires relativistic interactions, hence is much suppressed. Cohen calculated those cross sections and found that they are smaller by 6 to 8 orders of magnitude compared to their elastic scattering counterparts . Therefore we do not consider the asymmetric spin flip in our simulations.