Everhart-Thornley detector

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 1960 Thomas Eugene Everhart and R.F.M. Thornley presented in a publication detector is mainly used for imaging in a scanning electron microscope in order to enhance the secondary electron current is a very small sample.

Principle

The detector consists of a scintillator in a Faraday cage and a photomultiplier tube, and is therefore a scintillation counter. The electrons generate photons in the scintillator by cathodoluminescence, which in turn are received by the photomultiplier, amplified and converted into a voltage pulse. The special thing about this particular structure is the use of light guides which guide the photons from the scintillator to the photomultiplier outside the vacuum chamber.