High Speed X-Ray Reflectometry

Mark Henderson, David King, Trevor Dowling, Andrew Jackson and John White

We are currently developing an instrument -ultimately one that exploits the high radiation flux of a synchrotron source- that will record reflectivity measurements of fast, transient structural changes in chemical and biological processes at the air-water interface with sub-second resolution.  Present methods for the study of these materials are very powerful. ¹ However, there is a need to improve the time resolution of such studies from hours to fractions of one second (potentially to milliseconds with synchrotron radiation) so that faster chemical reactions and the relaxation processes of interfacial structures can be investigated in real time. ^{2   3}   Two energy dispersive analysers for the new reflectometer have been commissioned on our laboratory x-ray source, a commercial liquid nitrogen-cooled germanium detector and a Bragg rotor crystal analyser.  High speed reflectometry is a technique well suited to study the growth of oxide or protein films that can self-assemble at the air-water interface.

These experiments have been supported by grants from the Research Infrastructure Equipment Fund (REIF Grant RI 9939166) and the ANU Major Equipment Committee, a cash contribution from the University of Queensland and "in kind" contributions from the ANU and ANSTO.

[1]        Brown, A. S., Holt, S. A., Saville, P. M., White, J. W., Aust. J. Phys., 1997, 50, 391-405.

[2]        White, J. W., Brown, A. S., Garrett, R. F., King, D. J., Dowling, T. L., Aust. J. Phys., 1999, 52, 87-100.

[3]        Garrett, R. F., White, J. W., King, D. J., Dowling, T. L., Fullagar, W., Nucl. Instrum. Methods A, 2001, 467, 998-1000.