In physicsoptically stimulated luminescence OSL is a method for measuring doses from ionizing radiation. It is used in at least two applications:.
The method makes use of electrons trapped between the valence and conduction bands in the crystalline structure of certain minerals most commonly quartz and feldspar. The ionizing radiation produces electron-hole pairs: Electrons are in the conduction band and holes in the band.
The electrons that have been excited to the conduction band may become entrapped in the electron or hole traps. stimulation of light the electrons may free themselves from the trap and get into the conduction band.
From the conduction band they may recombine with holes trapped in hole traps. If the centre with the hole is a luminescence center radiative recombination centre emission of light will occur.
The photons are detected using a photomultiplier tube. The signal from the tube is then used to calculate the dose that the material had absorbed. The OSL dosimeter provides a new degree of sensitivity by giving an accurate reading as low as 1 mrem for x-ray and gamma ray photons with energies ranging from 5 keV to greater than 40 MeV. Radiation exposure dating OSL dosimeter's maximum equivalent dose measurement for x-ray and gamma ray photons is rem.
For beta particles with energies from keV to in excess of 10 MeV, dose measurement ranges from 10 mrem to rem. Neutron radiation with energies of 40 keV to greater than 35 MeV has a dose measurement range from 20 mrem to 25 Radiation exposure dating. In diagnostic imaging the increased sensitivity of the OSL dosimeter makes it ideal for monitoring employees working in low-radiation environments and for pregnant workers. To carry out OSL dating, mineral grains have to be extracted from the sample.
Occasionally other grain sizes are used. The difference between radiocarbon dating and OSL is that the former is used to date organic materials, while the latter is Radiation exposure dating to date minerals.
Events that can be dated using OSL are, for example, the mineral's last exposure to sunlight; Mungo ManAustralia's oldest human find, was dated in this manner. In archaeology, OSL dating is applied to ceramics: Recent OSL dating of stone tools in pushed the "out-of-Africa" date hypothesis of human migration back 50, years and added a possible path of migration from the African continent to the Arabian peninsula instead of through Europe.
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