Alpha And Beta Particles in a Diffusion Cloud Chamber

Note: The cloud chamber can be used without radioactive sources for muon displays.

This demonstration is a small cloud chamber setup.   A larger apparatus is available in the upper year labs.

1. Place the tray/styrofoam container on the leveling stand.
2. Fill the tray with dry ice pellets (two scoops).
3. Fill the bottom of the cloud chamber and wet the lining on its side walls with ethyl alcohol.
4. Place a thick metal plate on top of the dry ice, and place the chamber on top of the plate.
5. Level the setup.
6. Using lab jacks, adjust the Leitz projector (or some other light source) to shine into the chamber at a downward angle.
7. Allow the alcohol to cool down for 5 - 10 minutes
8. Insert the alpha/beta source through the corked opening on side of the chamber.

Method:

1. Turn on the slide projector / lamp and observe.
2. The long thin trails are from beta particles
3. The wider and denser clouds are from alpha particles.

Optional: 45VDC supply / battery to set up an electric field within the chamber.