Material:Vacuum

Vacuum is space devoid of matter. In x-ray scattering experiments, samples are often measured under vacuum conditions in order to minimize sample degradation and to reduce the background from air scattering.

As a material, vacuum can be considered to have an x-ray refractive index of exactly 1.0, to have zero contribution to scattering, and to have zero absorption. (Of course these are only strictly true for a perfect vacuum.)