Inelastic scattering of x-rays

The high intensity of x-rays emitted by synchrotron radiation sources provides the possibility of performing inelastic x-ray scattering with very high energy resolution,ΔE < 10 meV. This can be achieved by elastic scattering under extreme back reflection (Bragg angle near 90 degrees) from perfect Si single crystals as monochromator and analyser. Focussing by spherically bending the double grooved crystals increases the transmitted intensity. The first direct observation of phonon excitations with x-rays was performed with the inelastic x-ray scattering spectrometer. The measurement of the phonon dispersion curve of a Be single crystal is reported