High-energy X-rays or HEX-rays are very hard X-rays, with typical energies of 80–1000 keV (1 MeV), about one order of magnitude higher than conventional X-rays used for X-ray crystallography (and well into gamma-ray energies over 120 keV). They are produced at modern synchrotron radiation sources such as the Cornell High Energy Synchrotron Source, SPring-8, and the beamlines ID15 and BM18 at the European Synchrotron Radiation Facility (ESRF). The main benefit is the deep penetration into matter which makes them a probe for thick samples in physics and materials science and permits an in-air sample environment and operation. Scattering angles are small and diffraction directed forward allows for simple detector setups. High energy (megavolt) X-rays are also used in cancer therapy, using beams generated by linear accelerators to suppress tumors.

Advantages

High-energy X-rays (HEX-rays) between 100 and 300 keV bear unique advantage over conventional hard X-rays, which lie in the range of 5–20 keV They can be listed as follows:

Applications

With these advantages, HEX-rays can be applied for a wide range of investigations. An overview, which is far from complete: