photomultiplier

[ foh-tuh-muhl-tuh-plahy-er ]

noun

1. an extremely sensitive detector of light and of other radiation, consisting of a tube in which the electrons released by radiation striking a photocathode are accelerated, greatly amplifying the signal obtainable from small quantities of radiation.

photomultiplier

/ ˌfəʊtəʊˈmʌltɪˌplaɪə /

noun

1. a device sensitive to electromagnetic radiation, consisting of a photocathode, from which electrons are released by incident photons, and an electron multiplier, which amplifies and produces a detectable pulse of current

photomultiplier

/ fō′tō-mŭl′tə-plī′ər /

1. An electrical device designed for the detection of weak electromagnetic radiation, usually light, by amplifying the energy of the photons that strike it into stronger electrical signals. Photomultipliers are used in night-vision technology and in telescopes to detect light not strong enough to be visible by the unaided eye.
2. ◆ The most common photomultiplier is the tube photomultiplier ; it exploits secondary emission of electrons in a vacuum tube in the manner of an electron multiplier. When radiation strikes the cathode of a tube photomultiplier, electrons called photoelectrons are emitted and attracted to positively charged electrodes called dynodes. When they collide with the dynode, more electrons are released; these are in turn attracted to another dynode at a higher voltage to release yet more electrons, and so on. At the end of this process, there is a current flow at the anode that is strong enough to be easily detected.

Word History and Origins

Origin of photomultiplier¹

First recorded in 1935–40; photo- + multiplier

Example Sentences

If you think back to the example of putting a bucket outside during a rainstorm, these photomultipliers are like buckets that are so sensitive they can capture — and record — a single raindrop in a light drizzle.

From Science News For Students

To spot the small amounts of light left behind by individual particles, scientists use photomultiplier tubes, originally invented in the 1930s, which convert light into electrical signals.

From Science News

The tube is equipped with a mounting bezel to accept a camera or photomultiplier device.

From Project Gutenberg