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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.
Under 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.
It is concluded that sediment deposition was mainly forced by sediment supply from ploughing areas.
Two short-lived phases of incision during the first half of the XIX century were probably caused by a decrease of sediment supply due to a decline in the frequency of heavy precipitation events.
OSL works because all sediments have some natural radioactivity, caused by the presence of uranium, thorium and potassium isotopes in heavy minerals such as zircons.
We analyse the quartz or feldspar minerals in sand deposits.
K-feldspar has shown advantages over quartz for dating samples younger than 100 years, due to its more homogeneous equivalent dose ( determination procedures can be used to reveal the source material and/or quartz thermal history for the deserts in northern China.
The radiation causes charge to remain within the grains in structurally unstable "electron traps".
The trapped charge accumulates over time at a rate determined by the amount of background radiation at the location where the sample was buried.
Stimulating these mineral grains using either light (blue or green for OSL; infrared for IRSL) or heat (for TL) causes a luminescence signal to be emitted as the stored unstable electron energy is released, the intensity of which varies depending on the amount of radiation absorbed during burial and specific properties of the mineral.
The trapping sites are imperfections of the lattice — impurities or defects.