fotonásobiích

Fotonásobič, also known as a photomultiplier tube (PMT), is an extremely sensitive detector of light. It works by converting incident photons into an electrical signal. When a photon strikes the photocathode, it ejects one or more electrons through the photoelectric effect. These electrons are then accelerated by an electric field towards a series of electrodes called dynodes. Each dynode is held at a progressively higher positive voltage. When an electron strikes a dynode, it causes the emission of several secondary electrons. This process is repeated through multiple dynodes, resulting in a significant amplification of the original signal. The cascade of electrons eventually reaches the anode, where it is collected as a measurable electrical current. The gain, or amplification factor, of a photomultiplier tube can be very high, often in the order of 10^6 or more, making them suitable for detecting very faint light sources, such as those found in scientific experiments, medical imaging, and astronomical observations. Their ability to detect single photons makes them invaluable in applications where high sensitivity is paramount.