Time-resolved photoemission with a momentum microscope at LCLS II

The Linac Coherent Light Source (LCLS), the world’s first X-ray free-electron laser (FEL) has been in operation since 2009 and is currently emerging from a major upgrade. The upgraded LCLS II, which will see first light in 2023, employs a superconducting accelerator to increase the X-ray pulse repetition rate from 120 Hz to 1MHz, enabling experiments in a wide range of fields that are currently impossible. One prime example is angle-resolved photoemission spectroscopy (ARPES), which has proven to be a critical tool in advancing our understanding of quantum materials, such as high T_c superconductors and topological states of matter but has been of limited use at FELs due to space-charge effects. The high rep-rate of LCLS II will overcome this limitation, enabling viable time-resolved ARPES, PEEM, and XPD experiments. In this talk I will discuss our plans to deploy a momentum microscope endstation for time-resolved photoemission at LCLS II.