Protons and neutrons are themselves made of even smaller particles called quarks. These particles leave tiny tracks in the crystal structure of the zircon, which geologists count using a powerful microscope.
The more tracks there are, the longer the uranium has been decaying for.
Through optical filters the PSL signal is observed at shorter wavelengths (higher photon energies) than the stimulating light (“anti-Stokes” emission).
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.
Luminescence dating is a collective term for dating methods that encompass thermoluminescence (TL) and optically stimulated luminescence (OSL) dating techniques.
Like C dating, thermoluminescence is related to radioactive decay.
Thermoluminescence is produced by radioactive decay particles (electrons), trapped in mineral grains.
Luminescence dating is good for between a few hundred to (at least) several hundred thousand years, making it much more useful than carbon dating.
Two forms of luminescence dating are used by archaeologists to date events in the past: thermoluminescence (TL) or thermally stimulated luminescence (TSL), which measures energy emitted after an object has been exposed to temperatures between 400 and 500°C; and optically stimulated luminescence (OSL), which measures energy emitted after an object has been exposed to daylight.The dating range is dependent on the nature and state of conservation of the sample and the surrounding environment but is between a few thousands and a couple of million years.Since, ESR dating is best and most commonly applied to tooth enamel in archaeology PRINCIPAL: energy trapped in crystal imperfections depends on dose rate and time. Uranium atom produces high energy particles which leave straight "tracks" (10 - 20 µm) in glassy material The tracks are trails of destruction in the crystal lattice formed by particles emitted during spontaneous fission of 238U.This means that electrons and holes are accumulated over time in the crystal lattice induced by surrounding radiation.The age is obtained by calculating the dose received compared to the dose rate generated by the surrounding environment, mainly radioisotopes K, U, and Th.TL dating is a matter of comparing the energy stored in a crystal to what "ought" to be there, thereby coming up with a date-of-last-heated.