ELECTRON SPECTROSCOPIES
X-ray Photoelectron (XPS), Ultraviolet Photoelectron (UPS),
Auger Electron (AES), High Resolution Electron Energy Loss (HREELS)

Several ultra-high vacuum (UHV) systems at LASST are equipped for the study of surfaces and interfaces using electron spectroscopies (XPS, UPS, AES and HREELS). The Thin Film Synthesis and Characterization Facility includes instrumentation for XPS, UPS and scanning Auger Spectroscopy. The scanning Auger system can image and analyze samples with features down to sub-micron dimensions.

Adsorbates on surfaces can be studied with LASST’s high resolution electron energy loss spectrometer (HREELS). Energy resolution on the order of 1 meV can be achieved with this instrument. The instrument is also used in the development of a unique time-of-flight spectrometer.

LASST is equipped with a unique Controlled Atmosphere Photoelectron Spectrometer (CAPES) which permits surface characterization by XPS in ambient atmospheres at pressures on the order of 1 torr. The system consists of a commercial XPS instrument modified by the addition of a differentially pumped movable aperture assembly. The instrument can either be used as a UHV XPS instrument (p < 10^-9 torr) or, after insertion of the aperture, to analyze materials at ambient pressures of up to 1 torr. This unique configuration permits a variety of experiments that are otherwise impossible. For example, oscillating catalytic reactions of CO and O₂ on Pd surfaces have been followed in real time using this instrument. In addition, chemical reactions associated with creep cavitation failure of Inconel superalloys used in turbine blade technology have been studied under conditions simulating realistic operating environments.