Cloud chamber using Peltier cooling

Abstract

The design of a simple, compact, inexpensive cloud chamber is described and examples of particle tracks from cosmic rays and a radioactive sample are shown. A temperature gradient is established in the chamber through the use of a simple heater at the top and Peltier modules at the base, eliminating the need for dry ice. Using a few millilitres of isopropyl alcohol it starts to show particle tracks a few minutes after being switched on and operates for over two hours without any intervention. The cloud chamber is constructed using components that can be readily obtained at a total cost of about £40.