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Staying cool under scrutiny.

Author(s) : CAPERS M.

Type of article: Article

Summary

The article describes advances in scanning electron microscopy. Earlier microscopes depended on electrons produced by heating a filament. Thermionic emitters tend to have a low brightness which has to be increased using high accelerating voltages, causing deep sample penetration and loss of surface detail. A new process, field emission, operates at room temperature and generates a localised field around a crystal tungsten tip. The field strips electrons off the crystal. As no heat is generated, use can be made of cryogenic freezing of specimens. This is particularly valuable for wet specimens which would otherwise dry out, altering the detail to be studied. To maintain a frozen state, cryogenic refrigeration is required throughout the study time. D.W.H.

Details

  • Original title: Staying cool under scrutiny.
  • Record ID : 1993-1251
  • Languages: English
  • Source: Res. Technol. int. - 61-64; 4 fig.; 1 tabl.; 3 ref.
  • Publication date: 1992
  • Document available for consultation in the library of the IIR headquarters only.

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