Radiochemistry is a field of chemistry that involves the study of radioactive elements. It also deals with the production, identification, and use of such elements and their isotopes. Radiochemistry has benefited archaeology, biochemistry, and other scientific fields. Radiochemical techniques are often used in medicine to help diagnose disease and in various environmental studies.
A few radioactive elements, such as thorium and uranium, occur in nature. Others are created artificially. They can be produced in devices called particle accelerators by bombarding nonradioactive elements with high-energy particles. Elements also can be made radioactive in nuclear reactors by exposing them to large numbers of neutrons.
The isotopes of radioactive elements are called radionuclides or radioisotopes. They are widely used as tracers in certain kinds of research, especially the study of complex biological processes. This type of study involves tracing radionuclides through chemical reactions in organisms. The tracing is done with Geiger counters, proportional counters, and other detection devices.
A radionuclide is produced in minute quantities, and so it tends to plate out (accumulate) on the walls of its container before it can be used. Radiochemists prevent this by adding a small, precisely measured amount of a carrier element (nonradioactive element) to it.
Another important radiochemical technique is called neutron activation analysis. In this method, an object is exposed to neutrons, causing some of the elements in the object to become radioactive. These elements then emit radiation of certain energies. One of the uses of this method is the verification of the authenticity of old paintings. The paint used in old works of art differs in composition from the paint in recent paintings, and so it gives off different radiations.
