Research chemist, Air Force Materials Laboratory (MBM), Wright-Patterson Air Force Base, Ohio
Pages: 12 Published: Jan 1980
In order to utilize fully the newly developed electron and ion surface spectroscopies, the data from these methods must be treated carefully to assure quality and clarity both during and after the experiment. Signal conditioning during the experiment puts the data into proper form for recording and may include steps for amplifying, digitizing, discriminating, modulating, gating, transforming, and filtering.
After the acquisition and storage of data in digital form, several processing steps may be used to enhance, simplify, or otherwise make the data more useful to the operator. These data presentation improvements include smoothing, normalizing, differentiating, integrating, and performing other mathematical functions. An example of such a manipulation in Auger electron spectroscopy (AES) is the integration of the electron energy distribution curve, dN(E)/dE, which recovers the energy distribution, N(E). A second integration gives the original Auger electron current which may in certain cases be more effectively used for quantitative purposes than the usual peak-to-peak dN(E)/dE values. Subtraction methods may be used to emphasize the difference between a sample and the standard or between a bulk and a surface composition. The addition and subtraction of spectral features in an interactive graphics system allows synthesis of any composition for comparison with an unknown.
These techniques, combined with plotting subroutines, produce spectra of high quality and, in addition, simplify great amounts of information and present it in the form of depth profiles, histograms, or three-dimensional plots, which make the data more understandable.
surface analysis, data acquisition, digital methods, Auger electron spectroscopy (AES), ion scattering spectroscopy (ISS), secondary ion mass spectrometry (SIMS), X-ray photoelectron spectroscopy (XPS), ions, electrons
Paper ID: STP38656S