- channel electron multiplier (CEM)
A photoelectric detector consisting of a glass tube internally coated with a low conductance material. Voltage applied along the tube causes photoemission from the photocathode at the end of the tube exposed to the radiation, accelerating emission to the anode, which is located near the readout area. Secondary electrons are generated by collisions of the cascading electrons striking the channel walls. The device can multiply both electrons and high-energy protons.