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bubble chamber
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The bubble chamber is similar to a cloud chamber in application and 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 bubbles. 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 tridimensional image of an event to be captured. Bubble chambers
with resolutions down to a few
μ
m have been operated.
The whole chamber is subject to a constant magnetic field, which causes charged particles to travel in helical
paths whose radius is determined by their charge-to-mass ratios. Given that for all known charged long-lived
subatomic particles, the magnitude of their charge is that of an electron, their radius of curvature is thus
proportional to their momentum.
Although bubble chambers were very successful in the past, they are of only limited use in
current very-high-energy experiments
particle collisions
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