High-Energy Inelastic-Scattering Beamline for Electron Momentum Density Study

The advent of synchrotron radiation sources for well polarized and high-energy X-rays offers new opportunities for exploiting Compton scattering spectroscopy as a tool for investigating the electronic and magnetic structures of materials. Recent high-resolution Compton scattering experiments show the unique capability for the study of Fermiology-related issues and electron-electron correlation effects. Intense, high-energy and circularly polarized X-ray sources have improved magnetic Compton scattering spectroscopy from the point of statistical accuracy and momentum resolution. As a next advance, a high-energy inelastic scattering beamline dedicated to Compton scattering spectroscopies is being constructed at SPring-8. The light source is an elliptic multipole wiggler with a periodic length of 12 cm. The beamline includes two experimental stations: one is for high-resolution spectroscopy using 100-150 keV X-rays and the other is for magnetic Compton scattering experiments using circularly polarized 300 keV X-rays. The use of such high-energy X-rays makes it possible to carry out experiments efficiently on samples including heavier elements, such as high-T_c superconductors and 4f and 5f magnetic materials.