High resolution electron energy device and method

摘要

A device and method for obtaining high resolution of electron energy in an electron beam is described. The device has a resonance chamber containing a gas which exhibits a narrow scattering resonance at a specific electron energy value. The device utilizes the narrow resonance property of the gas to filter the electron energy spectrum at that energy value. A preferred embodiment is a spectrometer having an electron accelerator, an electromagnetic filter, a resonance chamber containing helium, and a trapped electron detector device. The electrons in the beam are accelerated and the beam is passed through an electromagnetic filter centered at approximately 20.614 eV. The filtered beam passes into a resonance chamber where the electrons have inelastic collisions with the helium atoms to produce the He21S excited state. The He21S scattering resonance has a narrow width of less than 0.001 eV at its energy threshold of 20.614 eV and serves as a filter. Due to the steepness of the initial rise of the resonance structure the resolution of the spectrometer is about 0.0001 eV. The trapped electron device then detects the flux density of the scattered electrons.