photomultiplier tube
electron multiplier tube that utilizes the multiplication of electrons by secondary emission to measure low light intensities. It is useful in television camera tubes, in astronomy to measure intensity of faint stars, and in nuclear studies to detect and measure minute flashes of light. The tube utilizes a photosensitive cathode, that is, a cathode that emits electrons when light strikes it, followed by a series of additional electrodes, or dynodes, each at a successively higher positive potential so that it will attract electrons given off by the previous dynode.
Learn more about photomultiplier tube with a free trial on Britannica.com.
| a scrap or morsel of food left at a meal. |
| an extraordinary or unusual thing, person, or event; an exceptional example or instance. |
Dictionary.com presents 366 FAQs, incorporating some of the frequently asked questions from the past with newer queries.