This technique is based on the principle that all objects absorb radiation from the environment.
This process frees electrons within minerals that remain caught within the item.
Many factors can spoil the sample before testing as well, exposing the sample to heat or direct light may cause some of the electrons to dissipate, causing the item to date younger.
Because of these and other factors, Thermoluminescence is at the most about 15% accurate.
The half-life of potassium-40 is 1.3 billion years, far longer than that of carbon-14, allowing much older samples to be dated.
Potassium is common in rocks and minerals, allowing many samples of geochronological or archeological interest to be dated.
Particular isotopes are suitable for different applications due to the type of atoms present in the mineral or other material and its approximate age.An additional problem with carbon-14 dates from archeological sites is known as the "old wood" problem.It is possible, particularly in dry, desert climates, for organic materials such as from dead trees to remain in their natural state for hundreds of years before people use them as firewood or building materials, after which they become part of the archaeological record.After yet another 5,730 years only one-eighth will be left.By measuring the carbon-14 in organic material, scientists can determine the date of death of the organic matter in an artifact or ecofact.Carbon-14 moves up the food chain as animals eat plants and as predators eat other animals. It takes 5,730 years for half the carbon-14 to change to nitrogen; this is the half-life of carbon-14.After another 5,730 years only one-quarter of the original carbon-14 will remain.One of the most widely used is potassium–argon dating (K–Ar dating).Potassium-40 is a radioactive isotope of potassium that decays into argon-40.Argon, a noble gas, is not commonly incorporated into such samples except when produced in situ through radioactive decay.The date measured reveals the last time that the object was heated past the closure temperature at which the trapped argon can escape the lattice.