Synchrotron Radiation Techniques and their Application to Actinide Materials

Abstract

Research on actinide materials, both basic and applied, has been greatly advanced by the general techniques available from high-intensity photon beams from x-ray synchrotron sources. The most important single reason is that such x-ray sources can work with minute (e.g., microgram) samples, and at this level the radioactive hazards of actinides are much reduced. We start by discussing the form and encapsulation procedures used for different techniques, then discuss the basic theory for interpreting the results. By reviewing a selection of x-ray diffraction (XRD), resonant elastic x-ray scattering (REXS), x-ray magnetic circular dichroism (XMCD), resonant and non-resonant inelastic scattering (RIXS, NIXS), dispersive inelastic x-ray scattering (IXS), and conventional and resonant photoemission experiments, we demonstrate the potential of synchrotron radiation techniques in studying lattice and electronic structure, hybridization effects, multipolar order, and lattice dynamics in actinide materials. CONTENTS I. Introduction 1 II. Samples and beamlines 3 References 49

Resonant inelastic x-ray scattering from U3O8 and UN

“…(a) We have extended the study of actinides with RIXS spectroscopy from the earlier successful work at the U N 4,5 edges on UO 2 [18] to examine the compounds U 3 O 8 and UN. These experiments represent a new form of spectroscopy performed at synchrotron sources, which is well adapted for looking in the future at small (<1 mg) active actinide samples [17,58] to establish the electronic structure over the first few eV. (b) Our results are consistent with our present understanding of U 3 O 8 as a localized 5f 1 system, and represents the first direct spectroscopic observation of the level structure.…”