AVS 50th International Symposium
    Applied Surface Science Thursday Sessions
       Session AS-ThA

Paper AS-ThA2
A PRBS-modulated TOF-HREELS Spectrometer with High Throughput and Multiplex Advantage

Thursday, November 6, 2003, 2:20 pm, Room 324/325

Session: Electron and Photon Spectroscopies
Presenter: B.G. Frederick, University of Maine
Authors: B.G. Frederick, University of Maine
Z. Yang, University of Maine
P. Kleban, University of Maine
Correspondent: Click to Email
We present an analysis of the factors that control the resolution, dynamic range, throughput-, and multiplex advantage of a novel time-of-flight (ToF) pseudo-random binary sequence (PRBS) modulated high resolution electron energy loss spectrometer (HREELS). We describe probability based spectral estimation methods for signal recovery that achieve a throughput advantage of 100-1000, a factor of 8-16 resolution enhancement, and account for the Poisson noise distribution in the measured data. The multiplex advantage achieved depends upon a number of factors, but significantly improves upon the multiplex disadvantage expected with the conventional cross-correlation or Hadamard transform methods when the detector signal is shot-noise limited. We describe how the optical properties of the chopper affect the PRBS modulated data within a theoretical framework and utilize trajectory calculations over an analytical potential to compare with data measured on azimuthally oriented polytetrafluoroethylene (PTFE, or Teflon) films.