Osl luminescence dating
Better still, unlike radiocarbon dating, the effect luminescence dating measures increases with time.As a result, there is no upper date limit set by the sensitivity of the method itself, although other factors may limit the method's feasibility.The signal from the tube is then used to calculate the dose that the material had absorbed.
Crystalline rock types and soils collect energy from the radioactive decay of cosmic uranium, thorium, and potassium-40.
The ionizing radiation produces electron-hole pairs: Electrons are in the conduction band and holes in the valence band.
The electrons that have been excited to the conduction band may become entrapped in the electron or hole traps.
Electrons from these substances get trapped in the mineral's crystalline structure, and continuing exposure of the rocks to these elements over time leads to predictable increases in the number of electrons caught in the matrices.
But when the rock is exposed to high enough levels of heat or light, that exposure causes vibrations in the mineral lattices and the trapped electrons are freed.