The cloud chamber is a scientific instrument that allows us to visualize the paths of charged particles such as electrons, protons, or alpha particles. It works based on the principle of supersaturation and condensation of vapor.
Construction: A cloud chamber consists of a sealed container filled with supersaturated vapor, usually alcohol or water. The container has a transparent window on one side to observe the particles inside. Inside the chamber, there is a piston or diaphragm, which can be compressed or expanded to control the pressure. Additionally, there is a cooling mechanism to lower the temperature and maintain the vapor in a supersaturated state.
Working:
Supersaturation: The cloud chamber is initially set up with the vapor in a supersaturated state. This means that the vapor is cooled to a temperature below its saturation point, creating a condition where it can condense upon exposure to a charged particle.
Particle detection: When a charged particle passes through the chamber, it ionizes the vapor molecules along its path. The ionized molecules act as nucleation sites for the condensation of vapor.
Vapor condensation: As the ionized vapor molecules act as nucleation sites, they attract and condense vapor around them, forming tiny droplets. These droplets are visible as a cloud in the chamber.
Particle track observation: The cloud formed by the condensation of vapor allows us to see the path of the charged particle. The track appears as a thin, curving line, showing the motion of the particle through the chamber.
Limitations:
Limited visibility: The cloud chamber can only detect charged particles that produce visible tracks. Neutral particles such as neutrons cannot be detected using this method.
Size limitation: The cloud chamber has a limited size, and the tracks of particles may become crowded in a larger chamber, making it difficult to distinguish individual tracks.
Sensitivity to contaminants: Contaminants present in the chamber, such as dust or impurities, can interfere with the visibility of particle tracks or create false tracks.
Limited particle energy range: The cloud chamber is most effective in detecting low-energy particles. High-energy particles may pass through the chamber without producing visible tracks.
Despite these limitations, the cloud chamber has played a significant role in the field of particle physics, allowing scientists to study the properties of charged particles and understand their behavior in different physical phenomena.
For more understanding see these lecture
https://www.youtube.com/watch?v=F38eyqZZskM
https://www.youtube.com/watch?v=SxAVv611cCs
