Thermoluminescence glow curves

Many polymers, after irradiation at low temperature, give off light when allowed to warm. This phenomenon of thermoluminescence depends not only on the chemical structure but also on crystal morphology. In polyethylene, for example, peaks in the thermoluminescence glow curve correspond, respectively, to the crystalline and the amorphous regions (9, 19, 22) (Figure 2). 

Fornaca-Rinaldi, G., and E. Tongiorgi The influence of grinding on the thermoluminescence glow-curves of limestones Summer Course on Nuclear Geology, Varenna, 1960, Laboratorio di Geol. Nucl., Pisa 254 (1960). 

The involvement of Qb has been independently confirmed by Wydrzynski and Inoue from the effect observed upon selective removal of Qb by a heptane/isobutanol extraction procedure that does not disturb the primary quinone Qa- The flash-induced thermoluminescence glow curve in the extracted chloroplasts is identical to that in the DCMU-treated chloroplasts, namely, the B-band is absent and in its place there is a D-band arising from charge recombination in [S2/S3 -Qa ]. By reconstituting lyophilized chloroplasts with native plastoquinone, the B band was restored. Also of interest is the observation that when phenyl-p-benzoquinone or 2,5-dimethyl-/i-benzoquinone was added to reconstitute the extracted sample, the glow curves were not only different from each other, but also did not display the normal, DCMU-generated D-band. These results indicate that the role ofthe extracted Qb in photosystem II may... 

Figure 16.9 Typical thermoluminescent glow curves, (a) Glow curve of CaS04 Mn heated at 6°C/min. (b) LiF (TLD-100) exposed to 10 R and heated at 20° C/min (from Ref. 12).

Figure 26. Thermoluminescent glow curves from synthetic fluorapatite after being irradiated with x-rays at 77 K (A) doped with 0.2% Mn. (B) 1-undoped 2-doped with 0.2% Mn 3-doped with 0.2% Ce 4-doped with 0.2% Eu. (C) 1- doped with 0.3% Mn 2-doped with 0.3% Mn with hydrothermal anneal at 973 K. Each peak represents the emptying of a different set of trapped electrons. Modified after Lapraz and Baumer (1983).

Fig. 1 Effect of low pH treatment on thermoluminescence glow curve 2 A pair) induced by a single flash excitation in the presence of 10 /iM DCMU at +10 C (a), -40 C (b) and -120 C (c). (A), untreated control membranes (B), low pH treated membranes (C), low pH treated then Ca-repleted membranes.

Similar measurements of thermoluminescence glow curve and EPR spectroscopy were done at varying excitation temperatures and the amplitudes of the two signals were plotted as a function of excitation temperature to determine the half inhibition temperature of to S2 transition in low pH treated PSII. As depicted in Fig. 4A, thermoluminescence peak height of the control untreated sample (O) showed a... 

Impact of PS Preparation Method on Thermoluminescence Glow Curves... 

Peixoto J, Oort A (1992) The physics of climate. American Institute of Physics, New York Prokic M (1977) Analysis of the thermoluminescence glow curves of natural barite. J Phys Chem Solid 38 617-622... 

In 1997, Chen and co-workers were the first to report the TL of a ZnS nanoparticle [161]. They prepared the ZnS nanoparticles using Zn(NOs)2 and NaiS as sources, and these nanoparticles were deposited on a quartz substrate for measurements. The average sizes of ZnS nanoparticles were estimated from the Debey-Scherrer formula and using XRD. The size of the nanoparticles prepared at RT, 50, 100, and 200 C, were 1.81, 2.50, 2.74 and 3.01 nm, respectively. Fig. 29 (a) illustrates the luminescence spectra of ZnS nanoparticles. It is seen that the luminescence intensity of trapped emission increases with decreasing size of the nanoparticles and the emission is blue-shifted as the size reduces. Fig. 29 (b) shows the thermoluminescence glow curves of the ZnS Mn nanoparticles. It is evident that the glow peak occurs around 360 K. It is to be noted that all samples show the glow peaks at almost the same position and the TL intensity is consistent with that of the surface fluorescence [161]. 

Figure 2 (B) shows thermoluminescence bands generated by mature wheat leaves [curves (a) and (b)] and by greening wheat leaves grown under intermittent illumination [curves (c) and (d)]. The continuous curves are for materials illuminated for I minute at -60 °C [curves (a) and (c)], and at-20 °C [curves (b) and (d)] the dashed curves are for the same materials without prior illumination. Each thermoluminescence band has its own (approximate) emission temperature Zy band( -45 °C where the subscript V stands for variable location ofthe band), A-band (-10 °C), B,-band (25 °C), B2-band (40 °C) and C-band (+55 °C). The C band is the major emission band in etiolated leaves [solid curves in (c) and (d)] and is apparently unaffected by prior actinic illumination [dashed curves in (c) and (d)]. Illumination of fully greened, mature leaves at -60 °C produces a weak Zy-band at -45 °C, a weakened C-band at 55 °C, a strong composite B-band, with Bi-band at 20 °C and B2-band shoulder at 40 °C, which together form the composite B-band. When the mature leaves were illuminated at -20 °C instead and immediately cooled [curve (b)], the glow curve is quite different a prominent A-band appears at -15/-20 °C, while the (Bj+B2)-band is much weaker and the Zy band is barely observable. Thus the A- and B-bands appear to be complementary to each other in amplitude illumination at -60 °C produces a strong B-band and no A-band, while illumination at -20° C produces predominantly A-band and much less B-band. Both the A...

Fig. 4. (A) Glow curves for spinach-leaf discs after a series of flashes (f-numbers). (B) Thermoluminescence intensity at 35 °C plotted as a function of flash number. Figure source Rutherford, Govindjee and Inoue (1984) Charge accumulation and photochemistry in leaves studied by thermoluminescence and delayed light emission. Proc Nat Acad Sci, USA 81 1109.

Glow curve In thermoluminescence, a graph of the amount of light emitted with temperature for a specific mineral. 

This phenomenon was observed with polymers some years ago [177—183]. The more recent investigations are due to Buben and Nikolskii [183]. These workers measured the emission from many amorphous and crystalline polymers and observed correlations between the temperature corresponding to the glow peak maxima and the structural transition temperatures of the materials. A detailed study of polyethylene thermoluminescence was made by Charlesby and Partridge [184]. The glow curve obtained after irradiation in vacuo possesses three peaks, a, j3 and y, whose luminescence intensities are proportional to the irradiation dose for doses below 5 x 104 rads. The maxima occurs, respectively, at —110, —65 and —27°C, when the total... 

Thermoluminescence (TL) is a widely used technique for the determination of shallow energy states in solids due to trapped electrons and holes. The basic principle is that an applied temperature will release trapped electrons when kT k = Boltzmann constant, and T = absolute temperature) is equivalent to the energy difference between the trapped state and the conduction band. Hence a type of spectrum is produced by slowly ramping the temperature of a material while its spectral emission is detected. Such a spectrum is called a glow curve, and usually plots all emitted photon intensity without discrimination of wavelength. After such a spectrum has been obtained, the full emission spectrum for every peak (i.e., temperature) in the glow curve can be obtained. In this way the ions associated with each trapping state can be identified (McKeever 1985). 

McKeever S. W. S. 1980. Thermoluminescence in LiF Analysis of the glow curves, Nucl. Instrum. Methods 175 19-20. 

Glow curve Plot of light intensity versus temperature as a sample is heated up during measurement of thermoluminescence (TL) (see Fig. la). 

FIGURE 1 (a) A thermoluminescence (TL) glow curve showing two distinct peale. (b) An optical dec curve generated during... 

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