HIstoric image taken from a cloud chamber at the Nevis Cyclotron Laboratory. The image shows diffusion cloud chamber tracks. A negative pi meson strikes a nitrogen nucleus and splits it into two particles, a proton and invisible neutrons. (4 prong star).
SCIENCE SOURCE/SCIENCE PHOTO LIBRARY
We present a sensitive diffusion cloud chamber which does not require any radioactive sources. A major difference from a commonly used chamber is use of a heat sink as its bottom plate. A result of a performance test of the chamber is given.
"A sensitive cloud chamber without radioactive sources" by Syoji Zeze, Akio Itoh, Ayu Oyama and Haruka Takahashi