Probing the Photoemission Delay in Single-Photon Double Ionization

X-ray free-electron laser (XFEL) facilities, which produce light pulses with attosecond scale duration, enable the exploration of multi-body interactions on ultrafast timescales. Combining these novel x-ray pulses with circularly polarized infrared laser pulses enables precision timing of photoemission phenomena. We investigate the retardation of valence photoelectrons released via single-photon, double ionization compared to direct ionization of core-level electrons in a neon target. Non-sequential ionization is mediated by electron correlation interactions; thus, we directly probe the timescale for electronic correlations. We use a novel covariance mapping technique to analyze the angular streaking data to suppress the effect of noise in our photoemission measurement.