Statistical analysis of hard X-ray radiation at PAL-XFEL facility performed by Hanbury Brown and Twiss interferometry

Hanbury Brown and Twiss interferometry experiment based on second-order correlations was performed at PAL-XFEL facility. The statistical properties of the X-ray radiation were studied within this experiment. Measurements were performed at NCI beamline at 10 keV photon energy in various operation conditions: Self-Amplified Spontaneous Emission (SASE), SASE with a monochromator, and self-seeding regimes at 120 pC, 180 pC, and 200 pC electron bunch charge, respectively. Statistical analysis showed short average pulse duration from 6 fs to 9 fs depending on operation conditions. A high spatial degree of coherence of about 70-80% was determined in spatial domain for the SASE beams with the monochromator and self-seeding regime of operation. The obtained values describe the statistical properties of the beams generated at PAL-XFEL facility.