Optically Stimulated Luminescence Dating Laboratory For Determining Age of Sediments

  • When a mineral is formed, all electrons are in the ground state.

  • Ionizing radiation—from naturally occurring radioactive minerals as well as from cosmic rays—ionizes atoms within silicate mineral grains like quartz and feldspar present in the sediments.

  • Due to ionization atoms and the electrons are transferred from ground state (valence band) to a higher energy state (conduction band).Usually electrons from conduction band loose energy and drop back to valence band.

  • However, all natural minerals contain structural defect sites at which electrons can be trapped. and these sites act as Traps.

  • Upon their return from conduction band electrons may get trapped in these structural traps (T).Heat or light can eject charges from traps T back into the conduction band.On loosing energy, electrons from conduction band drops back to its original site (L) and emits a photon (luminescence).