How do researchers explore nature on its most fundamental level? They build “supermicroscopes” that can resolve atomic and subatomic details. This won’t work with visible light, but they can probe the tiniest dimensions of matter with beams of electrons, either by using them directly in particle colliders or by converting their energy into bright X-rays in X-ray lasers. At the heart of such scientific discovery machines are particle accelerators that first generate electrons at a source and then boost their energy in a series of accelerator cavities.
Source:
https://phys.org/news/2019-08-atomic-trojan-horse-x-ray-lasers.html