3. Beta decay:

The compound nucleus almost instantaneously de-excites into a more stable configuration through emission of one or more prompt gamma rays ((p), with a half-life of 10-13 to 10-3 sec. In some cases, this new configuration will be stable.

More typically, the resulting configuration is a radioactive nucleus which further de-excites (or decays) by emission of a beta particle and one or more characteristic delayed gamma rays ((d), according to the unique half-life of the radioactive nucleus. Half-lives can range from a second to many years.

In the following equation, radioactive Al-28 decays to stable Si-28 through the loss of a beta particle. It also releases a gamma ray with a characteristic energy of 1779 keV .


Oregon State University Archaeometry Lab