channel photomultiplier, CPM, channel electron multiplier, CEM, continuous dynode
Channeltron detectors interact with electrons, positive and negative ions, hard and soft X-rays generating an electron avalanche from a primary particle. They work in a vacuum and generate massive secondary electron emissions with a high emission rate. These detectors are funnels in glass or ceramic bodies, which, depending on the design, have a horn, circular, sinusoidal, or spiral-shape which is vapor-deposited with a thin layer of semiconducting materials. If an electron hits the said layer, it is accelerated due to the applied high voltage and triggers an avalanche of secondary electrons in the subsequent collisions with the pipe wall, which can be measured as voltage pulses. The curved shape of the sewer pipe ensures that the secondary electrons generated when a wall impact hits the wall several times in order to trigger further electrons.