Relativistic three-dimensional Lippmann-Schwinger cross sections for space radiation applications

Abstract

Radiation transport codes require accurate nuclear cross sections to compute particle fluences inside shielding materials. The Tripathi semi-empirical reaction cross section, which includes over 60 parameters tuned to nucleon-nucleus (NA) and nucleus-nucleus (AA) data, has been used in many of the world's best-known transport codes. Although this parameterization fits well to reaction cross section data, the predictive capability of any parameterization is questionable when it is used beyond the range of the data to which it was tuned. Using uncertainty analysis, it is shown that a relativistic Three-Dimensional Lippmann-Schwinger (LS3D) equation model based on Multiple Scattering Theory (MST) that uses 5 parameterizations-3 fundamental parameterizations to nucleon-nucleon (NN) data and 2 nuclear charge density parameterizations-predicts NA and AA reaction cross sections as well as the Tripathi cross section parameterization for reactions in which the kinetic energy of the projectile in the laboratory frame (T Lab ) is greater than 220 MeV/n. The relativistic LS3D model has the additional advantage of being able to predict highly accurate total and elastic cross sections. Consequently, it is recommended that the relativistic LS3D model be used for space radiation applications in which T Lab > 220 MeV/n.

Are Further Cross Section Measurements Necessary for Space Radiation Protection or Ion Therapy Applications? Helium Projectiles

“…Moreover, total fragmentation cross section models can be used for normalizing and anchoring parametric models, such as DDFRG [12,13,119]. Werneth et al [146][147][148][149][150] developed a relativistic (kinematics) multiple scattering theory (RMST) for the prediction of reaction, elastic, total, and elastic differential cross sections for space radiation-relevant reactions. The fundamental nuclear constituents of the MST are defined as the nucleons, and the quark structure of individual nucleons is not considered.…”

“…relativistic three dimensional LS model (LS3D) agrees best with experimental data. Additional model improvements led to LS3D predictions of the reaction cross sections that were of the same fidelity to data as the Tripathi parameterizations [150]. In order to improve computational efficiency, a momentum-space formulation of the Eikonal approximation was developed.…”