ESA Science & Technology - XMM-Newton: light path of X-rays

The light path of X-rays through XMM-Newton (upper section). The spacecraft carries three telescopes each consisting of 58 nested, gold-coated, tube-like mirrors. The combination of parabolic and hyperbolic mirrors used is shown in a  cross section through one of the telescopes (middle section). X-rays that graze the mirror surfaces are reflected twice and focused onto a detector. The X-rays must graze the mirror at angles of 1° or even less, or they are likely to be absorbed (lower section).