Fotonásobi

Fotonásobi is a Slovak term that translates to "photomultiplier" in English. A photomultiplier, often abbreviated as PMT, is a highly sensitive detector of light. It is a vacuum tube that converts very weak light signals into measurable electrical currents. The fundamental principle behind a photomultiplier's operation involves the photoelectric effect and secondary emission. When photons, the particles of light, strike a photosensitive surface called the photocathode, they eject electrons. These electrons are then accelerated and strike a series of electrodes called dynodes, each at a progressively higher positive voltage. At each dynode, the impact of an incoming electron causes the emission of multiple secondary electrons. This cascading effect amplifies the initial signal, resulting in a large number of electrons for each photon detected. The final stream of electrons is collected by an anode, producing an electrical pulse that can be amplified and processed. Photomultipliers are widely used in scientific research and various applications where the detection of low light levels is crucial, such as in astronomy, medical imaging (like PET scanners), particle physics experiments, and in devices for measuring radioactivity. Their ability to detect single photons makes them invaluable tools for a broad range of sensitive measurements.