Negative electron affinity photocathodes as high-performance electron sources Part 2: Energy spectrum measurements

摘要

The energy spectra of electrons emitted from transmission-mode negative electron affinity photocathodes have been measured at high resolution using a parllel-plate retarding technique. The spectra from GaAs photocathodes have a basic structure that varies with temperature, activation layer qualitites, cathode thickness, and illuminating wavelength. A FWHM energy spread of approximately 50meV at room temperature has been achieved. Spectra from a GaAsP cathode show a markedly different structure and a much wider energy spread.