Asymmetry parameters in single ionization of He, Ne by XUV pulses

Fully differential cross-sections of single ionization of He and Ne atoms are studied by linearly polarized extreme ultraviolet (XUV) photons in the energy range of 22.1 eV–43.7 eV, using a reaction microscope. Photoelectron angular distributions and the β asymmetry parameters for He 1s ² electrons prove the reliability of our experiment, and the β asymmetry parameters extracted from the angular distributions of Ne 2p ⁶ electrons are obtained. By comparing with different theoretical calculations, it is found that the contribution of the electron correlation effect in Ne 2p ⁶ single ionization becomes increasingly important as the incident photon energy increases, while the relativistic effect is relatively low in the whole incident energy range. Our experimental β asymmetry parameters may serve as a significant reference to test the most elaborated theories in the field. The datasets presented in this paper, including the photoelectron angular distributions and β asymmetry parameters, are openly available at https://doi.org/10.57760/sciencedb.j00113.00073.