An apparatus for determining the secondary electron emission properties of nonconductors
The apparatus described allows the measurement of the secondary emission coefficient and the secondary electron energy distribution from nonconducting surfaces. The potential of the nonconducting surface is stabilized by a cathode very close to it. The use of an oscillatory primary beam allows a measurement of the secondary emission coefficient. The application of a sinusoidally modulated voltage sawtooth allows the determination of the emitted electron energy distribution and measures the potential of the emitting surface. The performance of the apparatus is demonstrated by results obtained from an amorphous magnesium oxide coating.
A measuring method to distinguish Auger from energy-loss peaks of the primary beam in secondary electron analysis
Introduction Auger peaks are measured from the Fermi level of the sample; some of the energy-loss peaks are referred to the energy of the exciting primary beam. There are also energy-loss peaks due to Auger peaks; they cannot be separated from each other. If one modulates both the exciting primary beam and the retarding grid of a spherical analyzer (outer cylinder for the mirror analyzer) one can tune the lock-in amplifier to a frequency and phase angle such that Auger or energy-loss peaks are detected separately.
Application of Automatic Tracking Correlation Filtering in Motored Spindle Dynamic Balancing
According to the information characteristics of the dynamic imbalance signal and the definition of correlation function,the principles and algorithm of relevant filter with automatic tracking is given.In labview development system,based on the principles of relevant filter with automatic tracking,the graphics programming of extracting the dynamic imbalance signal is developed.With this programming,the vibration signal including different frequency harmonic signals and noise is processed by simulation and on-site experiment.The results show that: through relevant filter with automatic tracking,the dynamic imbalance signal under different rotating speed can be extracted accurately,and it can meet the requirement of motored spindle dynamic balancing measurement.