Abstract: An x-ray exposure system that reduces the time required to evacuate an internal chamber of a vacuum vessel, uses a low-power laser to produce the plasma that generates the x-rays, and enables the sample to be maintained outside the vacuum vessel. The system includes a detachable cover member that hermetically seals the opening of the vacuum vessel. The cover member includes a through-hole that forms an x-ray irradiation window and is sealed by an x-ray transmission member. In the through-hole, an x-ray generation target is provided that is irradiated by an external laser beam, via a laser beam entry window.