High resolution electron energy loss spectrometer

An apparatus for producing and detecting high resolution electron energy loss spectra, said apparatus comprising:

• i) an electron gun generating a beam of electrons,
• ii) a first magnetic .OMEGA.-filter dispersing said beam according to electron energy,
• iii) an energy-selecting slit equipped with intensity sensors,
• iv) a stabilization means whereby the output of said intensity sensors is used to stabilize the position of said dispersed beam incident upon said energy-selecting slit,
• v) a sample illuminated by the electron beam transmitted through said energy-selecting slit,
• vi) a second magnetic .OMEGA.-filter dispersing electrons transmitted through said sample into an energy-loss spectrum,
• vii) a linkage means linking the magnetic fields inside said second .OMEGA.-filter to the magnetic fields inside first .OMEGA.-filter, and
• viii) an electron detector detecting the electron energy spectrum produced by said second .OMEGA.-filter,
• whereby instabilities of the high voltage supply of the electron gun and of the power supplies of the two .OMEGA.-filters are automatically compensated and so do not deteriorate the energy resolution of electron spectra detected by said electron detector.

A method for producing and detecting high energy resolution electron energy loss spectra, said method comprising:

• i) producing an electron beam from an electron gun,
• ii) dispersing said beam according to electron energies in a first energy analyzer,
• iii) monochromating the beam by selecting a small range of energies of said beam with an energy-selecting slit equipped with intensity-sensing means,
• iv) stabilizing the position of said beam incident upon said energy-selecting means using the output of said intensity-sensing means,
• v) transmitting the monochromated beam through a thin sample,
• vi) dispersing the beam transmitted through said sample into an energy-loss spectrum in a second energy analyzer,
• vii) linking the energy selected by said second energy analyzer to the energy selected by said first analyzer by a linking means, and
• viii) detecting the electron energy spectrum produced by the second energy analyzer by a detector means,
• whereby instabilities of the high voltage supply of the electron gun and of the power supplies of the two energy analyzers are automatically compensated and so do not deteriorate the energy resolution of electron spectra detected by said detector means.