Science dictionary - scientific encyclopedia

Full text search :

Geiger counter (Geiger-MÃ¼ller tube)

An instrument for counting photons of ionizing radiation (see the diagram). It consists of a tube containing a gas (typically argon) at low pressure; a potential difference is maintained between a central rod (the anode) and the casing (the cathode). The electric field in the tube is just below the threshold required for ionization, so even a low-energy electron can ionize an atom of the gas. When incident radiation ionizes a gas atom, the free electron is accelerated towards the anode, causing more ionization on its way, which in turn causes further ionization. Thus a pulse of current flows, which is amplified and counted. Named after Hans Wilhelm Geiger (1882-1945) and Walther MÃ¼ller.

{img src=show_image.php?name=image_07_04.gif }

Bookmark this page:

<< former term		next term >>
Ge		Geiger-Marsden experiment

Other Terms : vinyl chloride | apogee | pacemaker

Geiger counter (Geiger-MÃ¼ller tube)

<< former term

next term >>

Ge

Geiger-Marsden experiment