CEMs are detectors which respond to charged particles, hard and soft X-rays, and ultraviolet radiation. Through the process of secondary electron emission a CEM is capable of detecting a particle or photon that has entered its funnel-shaped input aperture. These primary particles generate secondary electrons that are accelerated down the channel by a positive bias. Upon striking the interior surface of the channel walls these electrons then generate further secondary electrons. The resulting avalanche process produces an easily detectable output pulse of charge containing up to 10e8 electrons with a duration (FWHM) of about 10 nanoseconds.
Outstanding features of the CEMs Series KBL include compact size and ruggedness. The CEMs are specially designed for easy mounting. In contrast to CEMs constructed entirely of glass, the CEM Series KBL are fabricated from ceramic material that has been processed with a CNC controlled milling machine or lathe before sintering. The inner wall is coated with hydrogen-reduced lead oxide glass having properties of secondary electron emission. A layer of silver extending from the funnel-shaped input aperture and the output end of the CEM to holes in the ceramic body establishes electrical contact.

These detectors found their first application in space research. Because of their resistance to physical shock and small size they meet the requirements for system components for rockets, satellites and space craft. They were used successfully in the GAS instrument for the detection of interstellar neutral gas on board the ULYSSES space probe. Their utilization in the Russian Mars'94 and the IBS-experiment on board the CASSINI space probe as well as in the HYDRA instrument on board the POLAR satellites has led the CEM KBL Series to become within only a few years the standard detectors used in space instrumentation.

The CEMs ceramic body also serves as an insulator making possible the development of compact arrays of single channels stacked together that allow a spatial resolution as well as simultaneous read out of all channels. Examples of these arrays are shown in this catalogue.