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Detector for Electron Beams

IP.com Disclosure Number: IPCOM000051658D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 52K

Publishing Venue

IBM

Related People

Coufal, H: AUTHOR [+2]

Abstract

In conventional energy loss spectroscopy, thin films are irradiated wi a monochromatic beam of electrons. The energy of the transmitted electrons is analyzed in order to obtain data on the loss of energy by the electrons in the sample. In Fig. 1, a schematic is shown of a typical energy loss spectrometer.

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Detector for Electron Beams

In conventional energy loss spectroscopy, thin films are irradiated wi a monochromatic beam of electrons. The energy of the transmitted electrons is analyzed in order to obtain data on the loss of energy by the electrons in the sample. In Fig. 1, a schematic is shown of a typical energy loss spectrometer.

An electron beam gun (EBG) supplies a monochromatic beam of 30 KeV electrons that impinges on a thin film. A certain amount of energy E is deposited in the film which corresponds to the excitation of valence and core electrons. The transmitted electron beam is subsequently energy analyzed by a magnetic field that spatially separates the electrons in, say, the X direction. The detector must be able to discriminate electrons according to the number of them which arrive as a function of X. Since X is a function of electron energy, then a plot of X against some response from the detector gives an energy loss spectrum. A problem in energy loss spectroscopy is obtaining a suitable detector; hence, for this reason, we describe a method and several simple detectors based on this reason for electron energy loss spectroscopy.

Chopped high energy radiation that is absorbed in any material creates thermoelastic and thermoacoustic waves which can be detected by acoustical methods, i.e., directly by piezoelectric pickups. Using the time that a wave needs to travel from the point where the energy is absorbed to the detector, different areas may be discriminated at the absorber. Examples using an acoustic or thermal delay time for discrimination are given in Figs. 2, 3, 4 and 5. The devices are cheap (e.g., BaTiO(3) delay line and an absorbing layer that could be an organic thin film). These could be produced with high spatial and/or time resolution.

Fig. 2 sh...