Recent results on the thermoluminescence properties of diaspore

Abstract

[1] The presence of hydrated diaspore (a-AlOOH) on the Martian surface allows us to speculate that this material could act as: a-Al 2 O 3 precursor and water source. In this study, new analytical data on the thermoluminescence (TL) properties of natural diaspore from Goian (Pontevedra, Spain) in the UV-blue spectral region are reported. The results indicate that it could be also used as a dosimeter for dating purposes, since it possesses an acceptable sensitivity to radiation, reproducibility, linear dose response in the studied range (up to 100 Gy), and a high stability of the relative TL emission after six months of storage. Some physical trapping parameters for each irradiated curve (trap depth, pre-exponential factor, intensity and peak position) are estimated assuming first order kinetics for the 180°C TL peak.

Blue thermoluminescence emission of annealed lithium rich aluminosilicates

“…As shown in Figure 3 (left-hand plots corresponding to non-annealed Li-rich aluminosilicates), the temporal evolution of the TL emission of this material is close to other materials previously studied [20] starting with an initial rapid decay (ca. 75-80%) and maintaining stability from about 30 days onwards.…”

“…The group of components that produce this peak has been also detected in the TL glow curves obtained for different irradiated natural quartzes [19] and aluminosilicates (e.g. microcline, a K-rich feldspar [20]), so it could be intrinsically associated with the Si-O bonds in the lattice, regardless of the type and concentration of impurities and the lattice structure. Non-annealed samples (Fig 2a, 2c and 2e) show slight differences depending on the dopant concentration.…”

Study of aluminium oxide from high-alumina refractory ceramics by thermoluminescence

“…Therefore, it could be accepted that the intensity of this emission is proportional to the concentration of traps given by the presence of different types or the concentration of divalent impurities. Both the value of activation energy and the frequency factor (s), that informs the probability per second for the release of a trapped charge carrier of the experimental TL spectra, are well correlated with the theoretical calculations made by Guissi et al (1999) and Correcher et al (2003b) corresponding to alpha alumina and diaspore, respectively (table 1). The value of the FOM is lower than 4% that indicates an acceptable good fitting (Balian and Eddy 1977).…”

“…This peak has also been detected in Al 2 O 3 : C that is usually employed for the estimation of environmental doses (Guissi et al 1999;Yukihara et al 2003) and in natural diaspore (Correcher et al 2003b). It happens despite (i) this TL emission stems from aluminium oxide instead of diaspore, which possesses a different structure and (ii) its origin formed initially in oxidizing atmosphere and subsequently maintained in depleted oxygen atmosphere.…”

“…The natural TL glow curves show the appearance of two peaks at about 157 and 177°C, which is characteristic of materials containing Al-O bonds, and (above 200-220°C) a very complex structure consisting of a broad distribution typically observed in several natural materials (such as diaspore, an aluminium oxo-hydroxide -α-AlOOH-) (Correcher et al 2003b). The TL physical trapping parameters for the curve (trap depth in eV, E, frequency factor in s -1 , s, intensity of the maximum in arbitrary units, a.u., I max , peak position in °C, T max , and figure of merit in percentage (FOM), parameter that indicates the goodness of the fitting) were estimated using the GCA program.…”