Practical Electron Microscopy and Database

A single-channel electron detector behind the slit of an energy filter produces an electrical signal proportional to the electron intensity at each energy loss. This system normally consists of a scintillator and a photomultiplier tube. This simple system works well but provides noisy data at high-energy loss, where the electron intensity is very weak. The reason lies not in the photomultiplier tube, which is a low noise detector, but in the fact that only a small range of energy loss is sampled at any event, resulting in pronounced noise due to the limited number of electrons being recorded.