An X-ray Free Electron Laser (XFEL) is a powerful tool that produces extremely bright and coherent X-ray beams. It uses a stream of high-speed electrons, which are accelerated and then passed through a magnetic structure called a undulator. This process causes the electrons to emit X-rays in a highly synchronized manner, resulting in intense and short pulses of X-ray light. XFELs are used in various fields, including materials science, biology, and chemistry, to study the structure and dynamics of matter at the atomic level. They enable researchers to capture rapid processes, such as chemical reactions and protein folding, providing insights that are difficult to achieve with traditional X-ray sources.