Geiger counter

American  

noun

1. an instrument for detecting ionizing radiations, consisting of a gas-filled tube in which electric-current pulses are produced when the gas is ionized by radiation, and of a device to register these pulses: used chiefly to measure radioactivity.

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Geiger counter British  

/ ˈɡaɪɡəˈmʊlə /

noun

1. an instrument for detecting and measuring the intensity of ionizing radiation. It consists of a gas-filled tube containing a fine wire anode along the axis of a cylindrical cathode with a potential difference of several hundred volts. Any particle or photon which ionizes any number of gas molecules in the tube causes a discharge which is registered by electronic equipment. The magnitude of the discharge does not depend upon the nature or the energy of the ionizing particle Compare proportional counter

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Geiger counter Scientific  

1. An electronic instrument that detects and measures nuclear radiation, such as x-rays or gamma rays. The Geiger counter consists of a gas-filled tube with a charged electrode connected to a counter. As radiation passes through the gas it ionizes atoms along its path. The ions are attracted to the charged electrode, creating pulses of electric current that are registered by the counter.

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Etymology

Origin of Geiger counter

First recorded in 1920–25; named after H. Geiger

Example Sentences

Or a substantial cockroach-like robot, off on a little trip to check out a nuclear accident, wearing a cute little backpack, fearless, regardless of what the Geiger counter says.

From Salon • May 13, 2025

The memoir displays Dunthorne’s gift for wry understatement and his doggedness as a researcher: he dug through archives, toted around a Geiger counter and even cooked food that his great-grandfather once consumed.

From Los Angeles Times • Mar. 26, 2025

Prosecutors also say he sent photographs showing "a dark rocky material" with a Geiger counter, which is used to measure levels of radiation.

From BBC • Feb. 21, 2024

For particularly radiation-sensitive steel applications, such as Geiger counter consoles, that fallout poses an obvious problem: it won’t do for a Geiger counter to flag itself.

From Scientific American • Jul. 28, 2023

But when Tiny Cooper lies to you about his heartbreak, the Geiger counter has tripped the hammer.

From "Will Grayson, Will Grayson" by John Green and David Levithan