Thermoluminescence

The early applications of thermoluminescence to the analysis and identification of rocks have been made by Deribere 1104), Garlick (105), Kohler and 

Leitmeier (106), Royer (107), Saurin (108), and Northrup and Lee (109), Saunders (110), Parks ill 1). Daniels et al (112), Lewis (113). and Bose et al. (114). The applications of thermoluminescence to problems of geological thermometry and age determination have been discussed by Ingerson (115), Zeller (116), Cairns (91L and Zurer (92). General reviews on TL include those by Daniels et al. (112). Bose et al. (114), Lancaster (93), Manche (90), and others (117-121,114). 

It is also possible to perform optical stimulation, viz. by irradiation with light the energy of which is sufficient to excite the electron from the trap into the conduction band. In certain applications this photostimulation plays an important role (see Chapter 8). 

Different aspects of TL in AIN ceramics were studied in our previous papers [27, 28, 30, 31, 34-38]. Studying peculiarities of TL after irradiation by the deuterium lamp with the wavelengths corresponding to excitation of the UV and Blue bands (243 and 298 nm, correspondingly), it was found that for both excitations the UV-Blue TL emission bands are shifted to the longer wavelengths compared to the corresponding PL emission bands - that is, the red shift is observed. At the same time, the Red band maintains the same position at 600 nm in TL as well as in PL emission spectra [40]. 

For TSL experiments the sample, under temperature control, is mounted in a vacuum light box and 

TSL is observable in most dielectrics in polymers the sample is commonly irradiated at liquid nitrogen temperature and heated to room temperature at a rate of approximately 3 C/min. TSL emission in many commercial polymers is negligible above room temperature and the information, which can be extracted from a single TSL measurement on the molecular environment of the trapped electrons, is not as precise as from ESR. The TSL spectrum of a polymer may contain both fluorescent and phosphorescent components. TSL provides information about ageing processes and can be used as a method for early recognition of damage in polymers. Fleming [488] has reviewed thermally stimulated luminescence (TSL) for the analysis of polymers. 

TSL should not be confused with chemiluminescence (cfr. Chp. 1.4.4), which is the emission of light originating in a chemical reaction. Thermoluminescence was reviewed [489]. For a book on thermoluminescence of solids the reader is referred to Mc-Keever [490]. 

No additive analysis applications were mentioned in Fleming s review on TSL [488]. 

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In thermoluminescence dating, a sample of the material is heated, and the light emitted by the sample as a result of the de-excitations of the electrons or holes that are freed from the traps at luminescence centers is measured providing a measure of the trap population density. This signal is compared with one obtained from the same sample after a laboratory irradiation of known dose. The annual dose rate for the clay is calculated from determined concentrations of radioisotopes in the material and assumed or measured environmental radiation intensities. 

Trace-element analysis of metals can give indications of the geographic provenance of the material. Both emission spectroscopy (84) and activation analysis (85) have been used for this purpose. Another tool in provenance studies is the measurement of relative abundances of the lead isotopes (86,87). This technique is not restricted to metals, but can be used on any material that contains lead. Finally, for an object cast around a ceramic core, a sample of the core material can be used for thermoluminescence dating. 

M. J. Aitken, Thermoluminescence Dating, Academic Press, Inc., London, 1985. 

Lithium fluoride is an essential component of the fluorine cell electrolyte 1% LiF in the KF 2HF electrolyte improves the wettability of the carbon anodes and lowers the tendency of the cells to depolarize (18). Thermoluminescent radiation dosimeters used in personnel and environmental monitoring and in radiation therapy contain lithium fluoride powder, extmded ribbons, or rods (19). 

Iodine vapor is characterized by the familiar violet color and by its unusually high specific gravity, approximately nine times that of air. The vapor is made up of diatomic molecules at low temperatures at moderately elevated temperatures, dissociation becomes appreciable. The concentration of monoatomic molecules, for example, is 1.4% at 600°C and 101.3 kPa (1 atm) total pressure. Iodine is fluorescent at low pressures and rotates the plane of polarized light when placed in a magnetic field. It is also thermoluminescent, emitting visible light when heated at 500°C or higher. 

A dosimeter is used to collect cumulative evidence of exposure to radiation and is worn as a badge. Dosimeters contain a thermoluminescent material such as lithium fluoride. Any incident radiation knocks electrons out of the flu-... 

Jorgensen CK (1976) Narrow Band Thermoluminescence (Candoluminescence) of Rare Earths in Auer Mantles. 25 1-20... 

Thermoluminescence. Thermoluminescence is a property of some solids in which excitation by light or particle radiation is frozen in as trapped electrons and holes or a crystal defect. Subsequent heating allows relaxation of the excited state and emission... 

In a more general application, thermoluminescence is used to study mechanisms of defect annealing in crystals. Electron holes and traps, crystal defects, and color-centers are generated in crystals by isotope or X-ray irradiation at low temperatures. Thermoluminescent emission during the warmup can be interpreted in terms of the microenvironments around the various radiation induced defects and the dynamics of the annealing process (117-118). ... 

AitkenMJ (1985) Thermoluminescence dating. Academic Press, London... 

Roberts RG, Jones R, Smith MA (1990) Thermoluminescence dating of a 50,000 year old human occupation site in northern Australia. Nature 345 153-156 Schwarcz HP (1992) Uranium-series dating and the origin of modem man. In The Origin of Modem Humans and the Impact of Chronometric Dating. Aitken MJ, Stringer CB, Mellars PA (eds) Princeton University Press, Princeton, p. 12-16... 

Thermoluminescence Amount of light emitted at high temperature Pottery, burned flint Textbox 24... 

From a practical perspective, determining the time elapsed since the solid was at high temperature by thermoluminescence or optically simulated luminescence requires four successive stages ... 

Both the thermoluminescence and optically stimulated luminescence techniques are suitable for dating past heating events over a timespan ranging... 

MSssbauer spectroscopy Electron spin resonance spectroscopy Colorimetry Thermoluminescence Thermal analysis differential thermal analysis, dilatometry... 

Thermoluminescence measurements on a few milligrams of material scraped from fired-clay objects, such as pottery and figurines, can readily establish whether objects made of these materials are genuine antiquities, recent copies, or fakes. Chemical tests on what appeared to be a broken and restored terracotta statuette, purporting to be of Etruscan origin (from... 

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