The wave length of ~ 10-100 keV x-rays, and the interatomic distance in crystals, are roughly comparable, on the order of 1-0.1 nm. Shortly after the discovery of x-rays, around 1900, x-ray diffraction from well-characterized single crystals has been used for x-ray spectroscopy, and well-characterized x-rays have been used to measure all kinds of details about crystals. The most useful crystals for x-ray spectroscopy are silicon, germanium, and quartz, which are available in high purity for relatively low prices thanks to their extensive use in electronics.

The image is an example, a spherically curved quartz crystal. This crystal is about 40 mm in diameter; it keeps its 250 mm bending radius through optical contact with a quartz substrate. In this case example quartz' 10-11 crystal plane is parallel to the surface; this cut has 2d=0.6687 nm, hence it can be used for monochromatic imaging of x-rays with 0.6687 nm wavelength and maybe slightly shorter (when the reflection of x-rays from this crystal is perpendicular or at least close to 90 degrees, in first order). Quartz has many other 2d-spacings that are useful for x-ray spectroscopy and monochromatic imaging.

Ecopulse can supply these and other crystals, mounted on a cylindrical, spherical and even elliptical or aspheric substrates. A relatively small crystal with 10 mm diameter, say, may cost around $ 3,000, while larger crystals (as the one shown above) can be a few times expensive. Please inqquire about pricing, since the actual price depends on many other variables than only size.

Spectropolarimetry of x-rays using a single crystal is described by E. O. Baronova and M. M. Stepanenko in Plasma Phys. Controlled Fusion, v.45, 1113 (2003), and further discussed by N. R. Pereira in two published papers. One, JMOP v.45, p. 2563 (2007), can not be posted here but will be emailed to you on request (to pereira at ninorpereira@gmail.com), the original of the other, HEDP v.3, p.106 (2009), is available here .