imported>JimBurd at 22:35, 24 April 2024

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{{short description|Vessel filled with a superheated transparent liquid}}
[[File:BubbleChamber-fnal.jpg|thumb|[[Fermilab]]'s disused {{convert|15|ft|2|adj=on}} bubble chamber]]
[[File:Liquid hydrogen bubblechamber.jpg|thumb|The first tracks observed in [[John Wood (physicist)|John Wood]]'s {{convert|1.5|in|cm|adj=on}} [[liquid hydrogen]] bubble chamber, in 1954.]]

A '''bubble chamber''' is a vessel filled with a [[superheating|superheated]] [[transparency (optics)|transparent]] [[liquid]] (most often [[liquid hydrogen]]) used to detect [[electric charge|electrically charged]] particles moving through it. It was invented in 1952 by [[Donald A. Glaser]],<ref>{{cite journal
|author = Donald A. Glaser
|year = 1952
|title = Some Effects of Ionizing Radiation on the Formation of Bubbles in Liquids
|journal = [[Physical Review]]
|volume = 87 |issue = 4 |pages = 665
|doi = 10.1103/PhysRev.87.665
|bibcode = 1952PhRv...87..665G }}</ref> for which he was awarded the 1960 [[Nobel Prize in Physics]].<ref>
{{cite web
|url=http://nobelprize.org/nobel_prizes/physics/laureates/1960/
|title=The Nobel Prize in Physics 1960
|publisher=[[The Nobel Foundation]]
|access-date=2009-10-03
}}</ref> Supposedly, Glaser was inspired by the bubbles in a glass of [[beer]]; however, in a 2006 talk, he refuted this story, although saying that while beer was not the inspiration for the bubble chamber, he did experiments using beer to fill early [[prototype]]s.<ref>{{cite web
|author=Anne Pinckard
|date=21 July 2006
|title=Front Seat to History: Summer Lecture Series Kicks Off – Invention and History of the Bubble Chamber
|url=http://www.lbl.gov/Publications/Currents/Archive/Jul-21-2006.html#6
|work=Berkeley Lab View Archive
|publisher=[[Lawrence Berkeley National Laboratory]]
|access-date=2009-10-03
|archive-date=2017-12-24
|archive-url=https://web.archive.org/web/20171224093552/http://www2.lbl.gov/Publications/Currents/Archive/Jul-21-2006.html#6
|url-status=dead
}}</ref>

While bubble chambers were extensively used in the past, they have now mostly been supplanted by [[wire chamber]]s, [[spark chamber]]s, [[drift chamber]]s, and [[semiconductor detector|silicon detector]]s. Notable bubble chambers include the [[Big European Bubble Chamber]] (BEBC) and [[Gargamelle]].

__TOC__

==Function and use==
The bubble chamber is similar to a [[cloud chamber]], both in application and in basic principle. It is normally made by filling a large cylinder with a liquid heated to just below its [[boiling point]]. As particles enter the chamber, a [[piston]] suddenly decreases its pressure, and the liquid enters into a superheated, [[metastable]] phase. Charged particles create an ionization track, around which the liquid vaporizes, forming microscopic [[Liquid bubble|bubble]]s. Bubble density around a track is proportional to a particle's energy loss.

Bubbles grow in size as the chamber expands, until they are large enough to be seen or photographed. Several cameras are mounted around it, allowing a three-dimensional image of an event to be captured. Bubble chambers with resolutions down to a few [[micrometers|micrometers (μm)]] have been operated.

It is often useful to subject the entire chamber to a constant magnetic field. It acts on charged particles through [[Lorentz force]] and causes them to travel in [[helix|helical]] paths whose radii are determined by the particles' [[charge-to-mass ratio]]s and their velocities. Because the magnitude of the charge of all known, charged, long-lived subatomic particles is the same as that of an [[electron]], their radius of curvature must be proportional to their [[momentum]]. Thus, by measuring a particle's radius of curvature, its momentum can be determined.

<gallery widths="200px" heights="200px">
File:Recording bubble chamber.jpg|A bubble chamber recording from [[CERN]]
Image:Bubble-chamber.svg|A bubble chamber
</gallery>

=== Notable discoveries ===
Notable discoveries made by bubble chamber include the discovery of [[neutral current|weak neutral current]]s at [[Gargamelle]] in 1973,<ref>{{cite web
|url=http://public.web.cern.ch/public/en/About/History73-en.html
|title=1973: Neutral currents are revealed
|publisher=[[CERN]]
|access-date=2009-10-03
|archive-url=https://web.archive.org/web/20101116170114/http://public.web.cern.ch/public/en/About/History73-en.html
|archive-date=2010-11-16
|url-status=dead
}}</ref> which established the soundness of the [[electroweak theory]] and led to the discovery of the [[W and Z bosons]] in 1983 (at the [[UA1 experiment|UA1]] and [[UA2 experiment]]s). Recently, bubble chambers have been used in research on [[Weakly interacting massive particles|weakly interacting massive particles (WIMP)]]s, at SIMPLE, [[COUPP]], [[PICASSO]] and more recently, [[SNOLAB#Experiments|PICO]].<ref>
{{cite web
|url=http://www-coupp.fnal.gov/
|title=COUPP experiment – E961
|publisher=[[COUPP]]
|access-date=2009-10-03
}}</ref><ref>
{{cite web
|url=http://www.picassoexperiment.ca/experiment.php
|title=The PICASSO experiment
|publisher=[[PICASSO]]
|access-date=2009-10-03
}}</ref><ref>
{{cite web
|url=http://www.picoexperiment.com/
|title=The PICO experiment
|publisher=[[SNOLAB#Experiments|PICO]]
|access-date=2016-02-22
}}</ref>

==Drawbacks==
Although bubble chambers were very successful in the past, they are of limited use in modern very-high-energy experiments for a variety of reasons:

* The need for a photographic readout rather than three-dimensional electronic data makes it less convenient, especially in experiments which must be reset, repeated and analyzed many times.
* The superheated phase must be ready at the precise moment of collision, which complicates the detection of short-lived particles.
* Bubble chambers are neither large nor massive enough to analyze high-energy collisions, where all products should be contained inside the detector.
* The high-energy particles may have path radii too large to be accurately measured in a relatively small chamber, thereby hindering precise estimation of momentum.

Due to these issues, bubble chambers have largely been replaced by [[wire chamber]]s, which allow particle [[energy|energies]] to be measured at the same time. Another alternative technique is the [[spark chamber]].

== Examples ==
* [[30 cm Bubble Chamber (CERN)]]
* [[81 cm Saclay Bubble Chamber]]
* [[2 m Bubble Chamber (CERN)]]
* [[Berne Infinitesimal Bubble Chamber]]
* [[Bevatron]], a particle accelerator with a liquid hydrogen bubble chamber
* [[Big European Bubble Chamber]]
* [[Holographic Lexan Bubble Chamber]]
* [[Gargamelle]], a heavy liquid bubble chamber which operated in CERN between 1970 and 1979.
* [[LExan Bubble Chamber]]
* [[PICO]], liquid freon bubble chamber searching for dark matter

==References==
{{Reflist}}

==External links==
{{Commons category}}
*{{cite web
|title=A step-by-step tutorial on how to read bubble chamber pictures
|url=http://teachers.web.cern.ch/teachers/archiv/HST2005/bubble_chambers/BCwebsite/index.htm
|archive-url=https://web.archive.org/web/20120307055407/http://teachers.web.cern.ch/teachers/archiv/HST2005/bubble_chambers/BCwebsite/index.htm
|archive-date=7 March 2012
|publisher=[[CERN]]
}}

{{Authority control}}

[[Category:Hydrogen technologies]]
[[Category:Particle detectors]]

Bubble chamber - Revision history

imported>JimBurd at 22:35, 24 April 2024