A bubble chamber is designed to detect charged particles through the tracks of bubbles present in a chamber consisting of liquefied gas or liquid hydrogen. It was invented by Donald Glaser in 1952.
This bubble chamber consists of a sealed cavity that is filled with a liquefied gas in order to reduce the inside pressure. Liquid hydrogen and helium are the most commonly used liquids in the bubble chambers, and a controlled device to maintain these gases in their liquid state. For applications requiring very dense liquids, a variety of organic compounds can be used.
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When the particles of liquid hydrogen enter the chamber, a piston immediately reduces the pressure inside this cavity, which in turn lowers the boiling point of liquid, leaving the liquid heated at the appropriate temperature.
When a charged particle passes via this heated liquid, it creates tiny gas bubbles. The size of the bubbles increases as the chamber expands, so that the bubbles can be illuminated and photographed.
Once the photographs are taken, the bubbles collapse upon recompressing the liquid. The bubble chamber is now ready for the next burst of particles.
In the presence of a magnetic field, the charged particles travel along a curved path, and the degree of curvature is dependent on the charge, speed and mass of the particle.
The key benefits of a bubble chamber include:
- It provides real three-dimensional images at a good spatial precision of 10-150 µm.
- It is capable of storing holographic events, which can in turn improve the resolution to 6µm.
- It can be subjected to a magnetic field for accurate detection of momentum.
- The number of interaction inside the bubble chamber can be increased by the higher density of the liquid.
- It ensures 4p solid angle coverage of particles.
Some of the major drawbacks of a bubble chamber include the following:
- Slow event reconstruction and film measurement.
- The liquid within the chamber serves as both a target and detector, and hence bubble chambers cannot be used with modern colliding-beam machines.
The bubble chamber is useful for analyzing high-energy particles. It is also used for precisely measuring rare decays with extremely short lifetimes.