What is Cloud chamber?
[[File:Radium hands in a cloud chamber (alpha particles).png|thumb|Alpha particles from a Radium source in a cloud chamber]] [[File:Radon220 decay in a cloud chamber.jpg|thumb|Radon220 decay in a cloud chamber]] [[File:PositronDiscovery.jpg|thumb|alt=track of subatomic particle moving upward through cloud chamber and bending left (an electron would have turned right)|Cloud chamber photograph of the first [[positron]] ever observed]] A '''cloud chamber''' is a sealed box with a [[supersaturation|supersaturated]] [[vapour]] of water or [[alcohol]]. When a [[charged particle]] (e.g. an [[alpha particle|alpha]] or [[beta particle]]) goes through it, the vapour is [[ionization|ionized]]. The resulting [[ion]]s act as nuclei, around which a mist forms from the vapour. The high energies of alpha and beta particles mean that a trail is left by ions produced along the path of the charged particle. These tracks have distinctive shapes (for example, an alpha particle's track is broad and shows more evidence of deflection by collisions, while an electron's is thinner and straight). When any uniform [[magnetic field]] is applied across the cloud chamber, positively and negatively charged particles will curve in opposite directions, according to the [[Lorentz force law]]. The cloud chamber was invented by [[Charles Wilson]] (1869–1959), a [[Scottish people|Scottish]] physicist who received the [[Nobel Prize in Physics]] in 1927 for this work. The first cloud chamber was made in 1911. The invention was used in the early days of [[atomic physics]]. It is often called the 'Wilson chamber'. Since then a number of other types of [[particle detector]]s have been invented. == References == * Das Gupta N.N. & Ghosh S.K. 1946. A report on the Wilson cloud chamber and its applications in physics. ''Reviews of Modern Physics''. '''18''', 225–365. ==Other websites== *[http://www.cloudylabs.fr/wwp/eng Many pictures of nuclear interaction and experiences]{{Dead link|date=January 2021 |bot=InternetArchiveBot |fix-attempted=yes }} *[http