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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 (and well into gamma-ray energies over 120 keV). They are produced at modern synchrotron radiation sources such as the beamline ID15 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. == 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: *High penetration into materials due to a strongly reduced photo absorption cross section. The photo-absorption strongly depends on the atomic number of the material and the X-ray energy. Several centimeter thick volumes can be accessed in steel and millimeters in lead containing samples. *No radiation damage of the sample, which can pin incommensurations or destroy the chemical compound to be analyzed. *The Ewald sphere has a curvature ten times smaller than in the low energy case and allows whole regions to be mapped in a reciprocal lattice, similar to electron diffraction. *Access to diffuse scattering. This is absorption and not extinction limited at low energies while volume enhancement takes place at high energies. Complete 3D maps over several Brillouin zones can be easily obtained. *High momentum transfers are naturally accessible due to the high momentum of the incident wave. This is of particular importance for studies of liquid, amorphous and nanocrystalline materials as well as pair distribution function analysis. *Realization of the Materials oscilloscope. *Simple diffraction setups due to operation in air. *Diffraction in forward direction for easy registration with a 2D detector. *Negligible polarization effects due to relative small scattering angles. *Special non-resonant magnetic scattering. *LLL interferometry. *Access to high-energy spectroscopic levels, both electronic and nuclear. *Forward scattering and penetration make sample environments easy and straight forward. *Neutron-like, but complementary studies combined with high precision spatial resolution. *Cross sections for Compton scattering are similar to coherent scattering or absorption cross sections. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「High-energy X-rays」の詳細全文を読む スポンサード リンク
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