Everhart-Thornley detector

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The Everhart-Thornley detector is a particle detector for secondary electrons , which is particularly low-noise and has a wide range of evaluable electrons. The detector, presented in a publication in 1960 by Thomas Eugene Everhart and RFM Thornley, is mainly used for imaging in the scanning electron microscope in order to amplify the very small secondary electron current of a sample.

principle

The detector consists of a scintillator in a Faraday cage and a photomultiplier , so it is a scintillation counter . The electrons generate photons in the scintillator through cathodoluminescence , which in turn are picked up by the photomultiplier, amplified and converted into a voltage pulse. The special feature of this special structure is the use of light guides, which guide the photons of the scintillator from the vacuum chamber to the photomultiplier outside.

literature

  • Thomas E. Everhart and RFM Thornley: Wide-band detector for micro-microampere low-energy electron currents . In: Journal of Scientific Instruments . tape 37 , no. 7 , 1960, pp. 246-248 , doi : 10.1088 / 0950-7671 / 37/7/307 .

Web links

  • Günter Bertsche: Everhart-Thornley detector. (pdf; 1.5 MB) In: The scanning electron microscope (SEM) - preparatory material for a practical experiment. University of Tübingen, p. 8 , archived from the original on June 26, 2013 ; accessed on July 8, 2016 (see - Section 1.3 deflection elements).