Channel Electron Multiplier ( CEM) or Channeltron

Channeltron® Single Channel Electron Multipliers (CEMs) are durable and efficient detectors of positive and negative ions as well as electrons and photons. Due to their low mass and high gain, electron multipliers are used in many nuclear physics labs and for space applications to count electrons and charged particles in pulse mode operation. 
PHOTONIS offers two different types of electron multipliers: Open and Single Channel.  Open multipliers are used in a number of mass spectrometry applications. Single channel electron multipliers are used in the detection core of many scientific instruments.