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Measurements should be taken on samples from different parts of the rock body.This helps to counter the effects of heating and squeezing, which a rock may experience in its long history.The energy liberated by the recombination can excite the luminescent centers, causing them to emit light.
The emission of light when certain solids are warmed, generally to a temperature lower than that needed to provoke visible incandescence.
Two characteristics of thermoluminescence distinguish it from incandescence.
The key elements of the dosimeters, thermoluminescent phosphors with deep traps, can store some of the energy absorbed from these radiations for very long periods of time at normal temperatures and release it as luminescence on demand when appropriately heated.
The brightness (or light sum) of the luminescence is a measure of the original radiation dose.luminescence that arises upon the heating of a substance that was previously excited by light or by hard radiation.
First, the intensity of thermoluminescent emission does not remain constant at constant temperature, but decreases with time and eventually ceases altogether.
Second, the spectrum of the thermoluminescence is highly dependent on the composition of the material and is only slightly affected by the temperature of heating.
Supporting this interpretation is the fact that after the thermoluminescence has been reduced to zero by heating, the sample can be made thermoluminescent again by exposure to one of a number of energy sources: x-rays and gamma rays, electron beams, nuclear particles, ultraviolet light, and, in some cases, even short-wave visible light (violet and blue).
A thermoluminescent material, therefore, has a memory of its earlier exposure to an energizing source, and this memory is utilized in a number of applications.
If a thermoluminescent material emits both thermoluminescence and incandescent light at some temperature of observation, the transient light emission is the thermoluminescence and the remaining steady-state emission is the incandescence.