Electron impact spectrometer with an improved source of monochromatic electrons

Claim 1

Apparatus for bombarding a sample with electrons having a limited number of discrete kinetic energies, characterized in that the apparatus comprises a gas discharge plasma light source generating a limited number of spectral lines, a gas container devoid of surface charges and disturbing fields containing a gas, means for injecting the light from said plasma light source into said gas container to generate photoelectrons having a plurality of energy levels from the gas molecules contained therein, said gas container also being provided with an aperture through which said generated electrons leave the container, an impact chamber for a sample to be analyzed, said impact chamber being located to position said sample to be bombarded by generated electrons leaving said aperture, energy discriminating means located between said aperture and said impact chamber for limiting the passage therethrough of electrons having only a single kinetic energy, and means for measuring the change in energy or diffraction of said generated electrons subsequent to impact with a sample.