The SpectroMicroscopy project is a collection of experiments designed to maximize the benefits of the undulator and monochromator on Beamline 7 at the Advanced Light Source. The experiments have a common theme of combining high spatial resolution and high energy resolution, for either mapping or structure determination with chemical-state selectivity[1,2]. There are a number of ongoing projects. These include the ultraESCA program, X-ray photoelectron diffraction (XPD), the PRISM photoelectron microscope, and two zone-plate microscopes, one for high pressure studies (STXM) and the other for ultra-high vacuum surface studies (SPEM). First results have been obtained from ultraESCA, XPD, PRISM, and STXM, portions of which are summarized here. The UHV zone-plate microscope is under construction, with the first images expected to be taken in the Spring of '96.
The photon energy range of the beamline is from about 60 eV to over 1000 eV. In this range the resolving power of the monochromator can be as high as 8000. The performance of the instruments we use is extraordinary, because the combination of the undulator, monochromator, and detectors are all at the state-of-the-art.
A schematic of the beamline layout is shown
in the figure above.The beamline has two 'micro-focus' stations, that use
adaptive grazing-incidence mirrors to put the monochromatic beam into areas
as small as 25 micron diameter (this was measured). We further use one
of the micro-focus positions as the object for the zone-plate microscopes,
which focus down the x-ray spot to 0.15 micron and lower, depending on
the zone-plate used.
References
1 "Photoemission Spectromicroscopy of Surfaces in Materials Science," B. P. Tonner, Synchrotron Radiation News 4, 27 (1991).
2 "Development of Electron Spectromicroscopy," B. P. Tonner et al., special issue of J. Elec. Spectros. in honor of D. Shirley.
email tonner@physics.ucf.edu.