An Accurate Technique to measure Angle-resolved Flash Desorption Spectra

A collimator system using four apertures is used to select a narrow beam of ∓ 2° opening from a single crystal sample. Since the apertures only "see" a small strip of the sample surface, signals from the edges of the crystal are eliminated. Detector is an ion gauge located off the beam axis to guarantee energy independence of the detected signals. A large number of measurements for varying coverage, different crystal orientations and different azimuth positions of the sample are described for the system H2/Ni and CO/Ni.