Three State Nuclear Decay


The Three State Nuclear Decay model simulates the radioactive decay of atomic nuclei in which the parent nucleus first decays into an intermediate state before decaying into a stable state. Although the decay of both the parent and intermediate nucleus (radionuclides) is spontaneous and unpredictable, the probability of decay of each radionuclide is constant and is usually known. This program displays a color-coded sample with N1 parent nuclides, N2 intermediate state nuclides, and N3 stable state nuclides. Users can set the initial numbers N1 and N2, the decay constants k1 and k2, and the time interval between measurements Δt before the simulation is run. The simulation counts the number of decay events and stops when all nuclides are in the stable state.

Check boxes display a plot and a table showing the time evolution of each state as well as the number of decay events in each time interval. The data plot allows users to compare the data generated by the random decay model with a differential equation-based model.


The Three State Nuclear Decay Java model was developed by Wolfgang Christian using the Easy Java Simulations (EJS) modeling and authoring tool created by Francisco Esquembere in Murcia, Spain. It was later converted from Java to JavaScript by Wolfgang Christian and Robert Hanson using the SwingJS system developed by Hanson and his students at St. Olaf College.

Updated 10 August 2020.