decay chain

Short definition from Wiktionary

Noun

1. 1
   A series of nuclides, such that one nuclide radioactively decays into another, which decays into another, and so on, until a stable nuclide is reached. For example, uranium-238 must undergo eight alpha decays and six beta decays in order to become stable lead-206; intermediate nuclides include uranium-234, radium-226, and radon-222.