FY05 LDRD Final ReportTime-Resolved Dynamic Studies using Short Pulse X-Ray Radiation

Nelson, A ; Dunn, J ; van Buuren, T ; Budil, K ; Sadigh, B ; Gilmer, G ; Falcone, R ; Lee, R ; Ng, A

Lawrence Livermore National Laboratory

关键词: Electronic Structure;    Time Resolution;    National Security;    75 Condensed Matter Physics, Superconductivity And Superfluidity;    Excitation;   

DOI  :  10.2172/885383
RP-ID  :  UCRL-TR-219068
RP-ID  :  W-7405-ENG-48
RP-ID  :  885383

美国|英语

来源: UNT Digital Library

【 摘 要 】

Established techniques must be extended down to the ps and sub-ps time domain to directly probe product states of materials under extreme conditions. We used short pulse ({le} 1 ps) x-ray radiation to track changes in the physical properties in tandem with measurements of the atomic and electronic structure of materials undergoing fast laser excitation and shock-related phenomena. The sources included those already available at LLNL, including the picosecond X-ray laser as well as the ALS Femtosecond Phenomena beamline and the SSRL based sub-picosecond photon source (SPPS). These allow the temporal resolution to be improved by 2 orders of magnitude over the current state-of-the-art, which is {approx} 100 ps. Thus, we observed the manifestations of dynamical processes with unprecedented time resolution. Time-resolved x-ray photoemission spectroscopy and x-ray scattering were used to study phase changes in materials with sub-picosecond time resolution. These experiments coupled to multiscale modeling allow us to explore the physics of materials in high laser fields and extreme non-equilibrium states of matter. The ability to characterize the physical and electronic structure of materials under extreme conditions together with state-of-the-art models and computational facilities will catapult LLNL's core competencies into the scientific world arena as well as support its missions of national security and stockpile stewardship.