Types of Radioactive Decay

• Alpha decay: the loss of an α-particle

  • α-particle: a helium nucleus

• Beta decay: the loss of a β-particle

  • β-particle: a high-energy electron

• Positron emission: the loss of a positron

  • Positron: a particle that has the same mass as, but an opposite charge to, that of an electron

• Gamma emission: the loss of a γ-ray

  • γ-ray: high-energy radiation that almost always accompanies the loss of a nuclear particle:

• Electron capture (K-capture): addition of an electron to a proton in the nucleus

  • The result of this process is that a proton is transformed into a neutron

Kinetics of Radioactive Decay

• Nuclear transmutation is a first-order process.

• The kinetics of such a process obey this equation:

  • ln(Nt/N0) = −kt

    • Nt is the mass, or number of particles at time t.

    • No is the original.

• The half-life of such a process is

  • 0.693/k=t1/2

  • Comparing the amount of a radioactive nuclide present at a given point in time with the amount normally present, one can find the age of an object.