Neutron Irradiated Dimes

There are many encased dime pieces in the marketplace from the American Museum of Atomic Energy. The pieces are encased in a round 25mm holder with a raised rim and a plastic cover over the dime. The dime does not show through the back, which is aluminum colored. In this article , I will describe the pieces, explain how and why they were made, and share some of the science related to the irradiation of the pieces.

The purpose of the dime irradiated at the American Museum of Atomic Energy, in Oak Ridge Tennessee, was to provide a dramatic demonstration of the principle of neutron activation for the public. Today, the museum is known as the American Museum of Science and Energy. In the late 1940s and early 1950s, dimes were also irradiated at Oak Ridge National Laboratory (ORNL).
When the dimes were prepared ahead of time, they were encased in a circular holder of aluminum with a plastic cover protecting the dime. Around the dime, under the plastic cover, there was also a label that said either "American Museum of Atomic Energy - Neutron Irradiated" or "Oak Ridge National Laboratory - Neutron Irradiated." The dime went into the chamber, was irradiated and came out. It's radioactivity was detected with a Geiger counter. With the sealed dimes, the holder and its dime are one product.

However, it was also possible for a customer to supply a dime for zapping. Visitors who did that got a plastic carrier that was not sealed. This was faster and allowed immediate satisfaction. These dimes could be removed from their holders. This same kind of blue plastic carrier made show at the New York World's Fair in 1964. Collectors beware, since the carriers were not sealed, there is no certainty that the dime they hold today had ever been irradiated.

The Irradiated dime promotion ran from 1949 to 1954, the American Museum of Atomic Energy gave out 250,000 samples. By 1967, the number was more than 1 million. The end of the program was brought about in 1964 when the U.S. Mint stopped using silver in its coins, at least inthe smaller denomination coins. Starting in 1965, the dimes were made out of nickel clad copper. For a time, the Museum purchased rolls of dimes from the local banks and separated out the old silver dimes to keep the program going.
Because visitors were able to supply thier own dimes to be irradiated there were many encasements made usingLiberty Head, or gemonly know as "Mercury Dimes," even though the Roosevelt dime was in production during the time period of the promotion. It is however, theoretically possible to assemble a year and mint set of irradiated Roosevelt dimes from 1946 threw 1964.

The dime was made radioactive by being bombarded with neutrons, which are atomic particles generated in a nuclear reactor. To make a dime radioactive, the coins metal, a silver-copper alloy, is subjected to bombardment by neutrons either by inserting it in a reactor or by exposure to a neutron emitter such as an antimony beryllium source. When the coin (a dime) is thus exposed, the neutrons strike some of the silver and copper atoms in the coin and convert them into radioactive isotopes.
Probably already more than you cared to know, and rather than go on explaining more of the specifics of the reaction and giving you long chemical formulas feel free to visitthe source of my information at Oak Ridge Associated Universities www .orau.org/ptp/collection/medalsmementoes/dimes.htm.
You can, if you want, still use this dime as money, even though it is quite different from the other silver in your coin collection. For it is radioactive! At this very minute it is giving off enough radiation to make a Geiger counter chatter. But because the amount of radiation is less than that given off by a luminous watch dial, the coin is perfectly safe to handle or carry.