Environmental Remediation Sciences Program at the Stanford Synchrotron Radiation Laboratory

Bargar, John R.

Bargar, John R.

关键词: Training;    Synchrotron Radiation;    Energy Range;    Kev Range;    Absorption;   

DOI  :  10.2172/896175
RP-ID  :  ERSD-95709-2006
RP-ID  :  None
RP-ID  :  896175

美国|英语

来源: UNT Digital Library

【 摘 要 】

Synchrotron radiation (SR)-based techniques provide unique capabilities to address scientific issues underpinning environmental remediation science and have emerged as major research tools in this field. The high intensity of SR sources and x-ray photon-in/photon-out detection allow noninvasive in-situ analysis of dilute, hydrated, and chemically/structurally complex natural samples. SR x-rays can be focused to beams of micron and sub-micron dimension, which allows the study of microstructures, chemical microgradients, and microenvironments such as in biofilms, pore spaces, and around plant roots, that may control the transformation of contaminants in the environment. The utilization of SR techniques in environmental remediation sciences is often frustrated, however, by an ''activation energy barrier'', which is associated with the need to become familiar with an array of data acquisition and analysis techniques, a new technical vocabulary, beam lines, experimental instrumentation, and user facility administrative procedures. Many investigators find it challenging to become sufficiently expert in all of these areas or to maintain their training as techniques evolve. Another challenge is the dearth of facilities for hard x-ray micro-spectroscopy, particularly in the 15 to 23 KeV range, which includes x-ray absorption edges of the priority DOE contaminants Sr, U, Np, Pu, and Tc. Prior to the current program, there were only two (heavily oversubscribed) microprobe facilities in the U.S. that could fully address this energy range (one at each of APS and NSLS); none existed in the Western U.S., in spite of the relatively large number of DOE laboratories in this region.