Bubble chamber

<h2 id="function-and-use">Function and use</h2>
<p>The bubble chamber is similar to a <a href="/facts/Cloud_chamber/89YSNbpN">cloud chamber</a>, both in application and in basic principle. It is normally made by filling a large cylinder with a liquid heated to just below its <a href="/facts/Boiling_point/E2BK9QoS">boiling point</a>.  As particles enter the chamber, a <a href="/facts/Piston/z7pN46u7">piston</a> suddenly decreases its pressure, and the liquid enters into a superheated, <a href="/facts/Metastable/H72SMWof">metastable</a> phase.  Charged particles create an ionization track, around which the liquid vaporizes, forming microscopic <a href="/facts/Liquid_bubble/99TogqIG">bubbles</a>. Bubble density around a track is proportional to a particle's energy loss.
</p><p>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 <a href="/facts/Micrometers/7eDFxD2L">micrometers (μm)</a> have been operated.
</p><p>It is often useful to subject the entire chamber to a constant magnetic field. It acts on charged particles through <a href="/facts/Lorentz_force/aq1Rc3SS">Lorentz force</a> and causes them to travel in <a href="/facts/Helix/BqC4AKwL">helical</a> paths whose radii are determined by the particles' <a href="/facts/Charge-to-mass_ratio/QaKpLt6B">charge-to-mass ratios</a> and their velocities. Because the magnitude of the charge of all known, charged, long-lived subatomic particles is the same as that of an <a href="/facts/Electron/L0KBo5cW">electron</a>, their radius of curvature must be proportional to their <a href="/facts/Momentum/TTkGv5eY">momentum</a>. Thus, by measuring a particle's radius of curvature, its momentum can be determined.
</p>

<h3>Notable discoveries</h3>
<p>Notable discoveries made by bubble chamber include the discovery of <a href="/facts/Neutral_current/eXCI2ldx">weak neutral currents</a> at <a href="/facts/Gargamelle/YzC4UGPB">Gargamelle</a> in 1973,<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> which established the soundness of the <a href="/facts/Electroweak_theory/QATz4dYF">electroweak theory</a> and led to the discovery of the <a href="/facts/W_and_Z_bosons/gAncY5XV">W and Z bosons</a> in 1983 (at the <a href="/facts/UA1_experiment/1RX0Qp6F">UA1</a> and <a href="/facts/UA2_experiment/mwrWwIeB">UA2 experiments</a>). Recently, bubble chambers have been used in research on <a href="/facts/Weakly_interacting_massive_particles/EbWC6o3w">weakly interacting massive particles (WIMP)s</a>, at SIMPLE, <a href="/facts/COUPP/ND26uAFh">COUPP</a>, <a href="/facts/PICASSO/ND26uAFh">PICASSO</a> and more recently, <a href="/facts/SNOLAB/qzyPjIvF">PICO</a>.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a><a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a><a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a>
</p>
<h2 id="drawbacks">Drawbacks</h2>
<p>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:
</p>
<ul><li>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.</li>
<li>The superheated phase must be ready at the precise moment of collision, which complicates the detection of short-lived particles.</li>
<li>Bubble chambers are neither large nor massive enough to analyze high-energy collisions, where all products should be contained inside the detector.</li>
<li>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.</li></ul>
<p>Due to these issues, bubble chambers have largely been replaced by <a href="/facts/Wire_chamber/BKstxtE9">wire chambers</a>, which allow particle <a href="/facts/Energy/wd8PrQM7">energies</a> to be measured at the same time. Another alternative technique is the <a href="/facts/Spark_chamber/2n40vcHl">spark chamber</a>.
</p>
<h2 id="examples">Examples</h2>
<ul><li><a href="/facts/30_cm_Bubble_Chamber_(CERN)/NwenBGcF">30 cm Bubble Chamber (CERN)</a></li>
<li><a href="/facts/81_cm_Saclay_Bubble_Chamber/EIBWXX5u">81 cm Saclay Bubble Chamber</a></li>
<li><a href="/facts/2_m_Bubble_Chamber_(CERN)/DKL21tvn">2 m Bubble Chamber (CERN)</a></li>
<li><a href="/facts/Berne_Infinitesimal_Bubble_Chamber/wYEpClbb">Berne Infinitesimal Bubble Chamber</a></li>
<li><a href="/facts/Bevatron/5llUlISh">Bevatron</a>, a particle accelerator with a liquid hydrogen bubble chamber</li>
<li><a href="/facts/Big_European_Bubble_Chamber/TyvqBYTC">Big European Bubble Chamber</a></li>
<li><a href="/facts/Holographic_Lexan_Bubble_Chamber/QQwax3DE">Holographic Lexan Bubble Chamber</a></li>
<li><a href="/facts/Gargamelle/YzC4UGPB">Gargamelle</a>, a heavy liquid bubble chamber which operated in CERN between 1970 and 1979.</li>
<li><a href="/facts/LExan_Bubble_Chamber/uKGeUVfM">LExan Bubble Chamber</a></li>
<li><a href="/facts/PICO/ND26uAFh">PICO</a>, liquid freon bubble chamber searching for dark matter</li></ul>

<h2 id="external-links">External links</h2>

Wikimedia Commons has media related to Bubble chambers.

<ul><li><a href="https://web.archive.org/web/20120307055407/http://teachers.web.cern.ch/teachers/archiv/HST2005/bubble_chambers/BCwebsite/index.htm">"A step-by-step tutorial on how to read bubble chamber pictures"</a>. <a href="/facts/CERN/y1gwRchm">CERN</a>. Archived from <a href="http://teachers.web.cern.ch/teachers/archiv/HST2005/bubble_chambers/BCwebsite/index.htm">the original</a> on 7 March 2012.</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Donald A. Glaser (1952). "Some Effects of Ionizing Radiation on the Formation of Bubbles in Liquids". Physical Review. 87 (4): 665. Bibcode:1952PhRv...87..665G. doi:10.1103/PhysRev.87.665. <a href="/wiki/Physical_Review" target="_blank">/wiki/Physical_Review</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>"The Nobel Prize in Physics 1960". The Nobel Foundation. Retrieved 2009-10-03. <a href="http://nobelprize.org/nobel_prizes/physics/laureates/1960/" target="_blank">http://nobelprize.org/nobel_prizes/physics/laureates/1960/</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Anne Pinckard (21 July 2006). "Front Seat to History: Summer Lecture Series Kicks Off – Invention and History of the Bubble Chamber". Berkeley Lab View Archive. Lawrence Berkeley National Laboratory. Archived from the original on 2017-12-24. Retrieved 2009-10-03. <a href="https://web.archive.org/web/20171224093552/http://www2.lbl.gov/Publications/Currents/Archive/Jul-21-2006.html#6" target="_blank">https://web.archive.org/web/20171224093552/http://www2.lbl.gov/Publications/Currents/Archive/Jul-21-2006.html#6</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>"1973: Neutral currents are revealed". CERN. Archived from the original on 2010-11-16. Retrieved 2009-10-03. <a href="https://web.archive.org/web/20101116170114/http://public.web.cern.ch/public/en/About/History73-en.html" target="_blank">https://web.archive.org/web/20101116170114/http://public.web.cern.ch/public/en/About/History73-en.html</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>"COUPP experiment – E961". COUPP. Retrieved 2009-10-03. <a href="http://www-coupp.fnal.gov/" target="_blank">http://www-coupp.fnal.gov/</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>"The PICASSO experiment". PICASSO. Retrieved 2009-10-03. <a href="http://www.picassoexperiment.ca/experiment.php" target="_blank">http://www.picassoexperiment.ca/experiment.php</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
<li id="fn:7"><p>"The PICO experiment". PICO. Retrieved 2016-02-22. <a href="http://www.picoexperiment.com/" target="_blank">http://www.picoexperiment.com/</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li>
</ol>

Bubble chamber open-in-new

Bubble chamber