NOTE

    The experiments herein require an alpha ray source and a gamma ray source. Suitable sources not exceeding the low radioactivity limits set by the U.S. Nuclear Regulatory Commission are available to the public.

    By far the least expensive “license free” or “exempt quantity” sources that could be found are made by The Nucleus Inc., Box R, Oak Ridge, Tennessee 37830. They provide an alpha ray source, containing polonium-210, designated as S-2. They also provide a gamma ray source, containing cesium-137, designated as S-6. The cost is $5 a piece.

    Each is a solid source housed within a one-inch diameter by l/4-inch thick plastic disc with identifying label. S-6 is completely sealed. But since sealing would block alpha rays, S-2 is uncovered. Therefore the user is cautioned not to disturb the polonium-210 coating recessed within the disc.

    These solid sources are regarded by the supplier as safe. But as with chemicals and tools, radioactive materials should be respected and used with care. A brochure on proper handling techniques and safety precautions comes with the sources.

    Shortly after this booklet was first published, we were informed of an even less expensive low-level source of alpha, beta, and gamma radiation. It is the silk gas mantle used for ordinary camping lanterns.

    Readily available in stores selling camping equipment, gas mantles cost around 60¢ for a bag of two. We recommend they be left in their sealed plastic bag.

   We were also told that coal, slate, and granite are possible  low-level  radioactive  sources.