bubble chamber: meaning, definition, pronunciation and examples

No, large bubble chambers are obsolete in frontier particle physics research. They were largely replaced in the 1980s by faster, electronic detectors like wire chambers and silicon trackers, which can handle much higher collision rates. Small bubble chambers are sometimes used for educational purposes or in rare low-background particle searches (e.g., for dark matter).

Liquid hydrogen is the most common and important filling, as it provides pure proton targets. Other liquids used include deuterium, propane, freon, and various heavier hydrocarbons, chosen based on the specific experimental needs (e.g., to study interactions with different nuclei).

The chamber contains a superheated liquid (heated above its normal boiling point but prevented from boiling by applied pressure). Just before a particle beam passes through, the pressure is suddenly reduced, making the liquid extremely unstable. Charged particles ionise atoms along their path, and these ions act as nucleation sites, triggering the formation of a trail of tiny vapour bubbles. These bubble tracks are then illuminated and photographed.

Its cycle time was slow. After each expansion to create bubbles and take a photograph, the chamber had to be re-compressed and the liquid allowed to settle, which took a significant fraction of a second. This limited the number of particle events that could be recorded compared to modern electronic detectors, which can record millions of events per second.

A vessel filled with a superheated transparent liquid (typically liquid hydrogen or a hydrogen compound) used to detect and visualise the paths of electrically charged subatomic particles as they pass through, creating tracks of tiny bubbles along their trajectories.

Bubble chamber is usually technical/scientific in register.

Bubble chamber: in British English it is pronounced /ˈbʌb.əl ˌtʃeɪm.bər/, and in American English it is pronounced /ˈbʌb.əl ˌtʃeɪm.bɚ/. Tap the audio buttons above to hear it.