SPACS: A semi-empirical parameterization for isotopic spallation cross sections

International audienceA new semi-empirical parameterization for residue cross sections in spallation reactions is presented. Theprescription named SPACS, for spallation cross sections, permits calculating the fragment production in protonandneutron-induced collisions with light up to heavy non-fissile partners from the Fermi regime to ultrarelativisticenergies. The model is fully analytical, based on a new parameterization of the mass yields, accountingfor the dependence on bombarding energy. The formalism for the isobaric distribution consists of a commonlyused functional form, borrowed from the empirical parameterization of fragmentation cross sections EPAX,with the observed suited adjustments for spallation, and extended to the charge-pickup channel. Structural andeven-odd staggering related to the last stage of the primary-residue deexcitation process is additionally explicitlyintroduced with a new prescription. Calculations are benchmarked with recent data collected at GSI, Darmstadtas well as with previous measurements employing various techniques. The dependences observed experimentallyon collision energy, reaction-partner mass, and proton-neutron asymmetry are well described. A fast analyticalparameterization, such as SPACS, can be relevant to be implemented in complex simulations as used for practicalissues at nuclear facilities and plants. Its predictive power also makes it useful for cross-section estimates inastrophysics and biophysics