bubble chamber, device for detecting charged particles and other radiation by means of tracks of bubbles left in a chamber filled with liquid hydrogen or other liquefied gas. It was invented in 1952 by Donald Glaser. The bubble chamber consists essentially of a sealed chamber to be filled with a liquefied gas and constructed so that the pressure inside can be reduced quickly. The liquid is originally at a temperature just below its boiling point boiling point, temperature at which a substance changes its state from liquid to gas. A stricter definition of boiling point is the temperature at which the liquid and vapor (gas) phases of a substance can exist in equilibrium.
..... Click the link for more information. . When the pressure is reduced, the boiling point becomes lowered so that it is less than the temperature of the liquid, leaving the liquid superheated. When a charged particle passes through this superheated liquid, it leaves a trail of tiny gas bubbles that can be illuminated and photographed. The track of a charged particle can be used to identify the particle and to analyze complex events in which it may be involved. If a magnetic field is present, the tracks of the particles will be curved, positively charged particles curving in one direction and negatively charged particles curving in the opposite direction. The degree of curvature depends on the mass, speed, and charge of the particle. Neutral particles can be detected indirectly by applying various conservation laws conservation laws, in physics, basic laws that together determine which processes can or cannot occur in nature; each law maintains that the total value of the quantity governed by that law, e.g., mass or energy, remains unchanged during physical processes.
..... Click the link for more information. to the events recorded in the bubble chamber or by observing their decay into pairs of oppositely charged particles. The bubble chamber is particularly useful for studying high-energy particles that would pass through a cloud chamber cloud chamber, device used to detect elementary particles and other ionizing radiation. A cloud chamber consists essentially of a closed container filled with a supersaturated vapor, e.g., water in air.
..... Click the link for more information. too quickly to leave a detailed enough track but which pass more slowly through the bubble chamber because of the greater density of the liquid. Liquid hydrogen and helium are commonly used in bubble chambers, with special equipment needed to maintain these gases in their liquid state (see low-temperature physics low-temperature physics, science concerned with the production and maintenance of temperatures much below normal, down to almost absolute zero, and with various phenomena that occur only at such temperatures.
..... Click the link for more information. ). For experiments requiring very dense liquids, a variety of organic compounds may be used. See elementary particles elementary particles, the most basic physical constituents of the universe.

Basic Constituents of Matter

Molecules are built up from the atom , which is the basic unit of any chemical element .
..... Click the link for more information. ; particle accelerator particle accelerator, apparatus used in nuclear physics to produce beams of energetic charged particles and to direct them against various targets. Such machines, popularly called atom smashers, are needed to observe objects as small as the atomic nucleus in studies
..... Click the link for more information. ; spark chamber spark chamber, in physics, device for recording the passage of elementary particles produced by reactions in a particle accelerator . Particles pass through a stack of metal plates or wire grids that are maintained with high voltage between alternate layers.
..... Click the link for more information. .

bubble chamber

Subatomic-particle detector that uses a superheated liquid which boils into tiny bubbles of vapour along the tracks of the particles. As charged particles move through the liquid, they knock electrons from the atoms of the liquid, creating ions. If the liquid is close to its boiling point, the first bubbles form around these ions. The observable tracks can be photographed and analyzed to measure the behaviour of the charged particles. Developed in 1952 by Donald Glaser, the bubble chamber proved very useful in the 1960s and '70s for the study of high-energy nuclear and particle physics.

bubble chamber [′bəb·əl ‚chām·bər]

(nucleonics)

A chamber in which the movements and interactions of charged particles can be observed as visible tracks in a superheated liquid, the tracks being gas bubbles that form along the paths of the moving particles.