CDAC Activity Report

Evans, W J

Lawrence Livermore National Laboratory

关键词: Raman Spectroscopy;    Training;    Hydrogen;    X-Ray Diffraction;    75 Condensed Matter Physics, Superconductivity And Superfluidity;   

DOI  :  10.2172/883593
RP-ID  :  UCRL-TR-215108
RP-ID  :  W-7405-ENG-48
RP-ID  :  883593

美国|英语

来源: UNT Digital Library

【 摘 要 】

We have received CDAC allotments of beam time at HPCAT that were used to carryout investigations that included angle-dispersive x-ray diffraction of beryllium at high pressures and inelastic x-ray scattering (x-ray Raman) of high pressure phases of water. These CDAC beam time allotments have permitted us to broaden and supplement the scope of our research. The beam time has also been used in experiments that had graduate student participants (Z Jenei and A Lazicki) and thus the experiments also incorporated a component of training and education. Water (H{sub 2}O) is a major constituent of terrestrial systems, and furthering our understanding of this ubiquitous system and hydrogen bonding structures impacts a broad range of systems; including geophysics, life sciences, the environment and technology development. Our inelastic x-ray scattering studies (x-ray Raman spectroscopy) of high-pressure phases of water and ice are aimed at addressing controversies regarding the high-pressure structure of water. Using the inelastic x-ray scattering system at HPCAT we have measured x-ray Raman spectra of water at 1 and 17 GPa. X-Ray Raman is a relatively new technique that provides data that is equivalent to x-ray absorption, but utilizes a hard x-ray to avoid short absorption lengths and surface effects to achieve a truly bulk measurement. These are extremely challenging measurements that rely on optimized experimental systems and the brilliance of a 3rd generation synchrotron source. The figure shown demonstrates our specially designed diamond and the general operation of the x-ray scattering system.