A spherically bent crystal spectrometer for inelastic X-ray scattering experiments

TIRAO, G.; C. CUSATIS; G. STUTZ

Campinas, Brasil

Congreso; X Reunion Anual de Usuarios del LNLS; 2000

In the last years, with the construction of high resolution synchrotron radiation-based x-ray spectrometers, IXSS (inelastic x-ray scattering spectroscopy) has proved to be a powerful tool for investigating electronic properties of many-electron systems1. The most important experimental requirement on energy analysing systems for inelastic x-ray scattering experiments in the regime of low and very-low energy and momentum transfer is the energy resolution, which should be about 1 eV if we are seeking single or collective excitations of valence electrons or about 1 meV if we are seeking collective ion excitations. High2-4 (~1 eV) and ultra-high5-7 (~1 meV) energy resolution could be achieved by using analyser crystals in backdiffraction geometry, i.e., Bragg angles close to 90o. Additionally, spherical focalisation is necessary in order to increase the flux of the analysed beam. In this report we present a new focusing backdiffracting analyser crystal, which will be the principal component of an experimental setup destined to carry out inelastic x-ray scattering experiments with high energy resolution at the XRD-beamline of the LNLS. The first IXSS-spectrum measured at LNLS will be shown.