Showing papers in "Radiation Measurements in 1994"

TL;DR: In this paper, the contribution of cosmic rays to the dose rates for TL/ESR dating depends on altitude, latitude and depth below ground level, and the effects are shown to be small over the past 500 ka in most circumstances.

TL;DR: In this paper, anomalous fading of infrared-stimulated luminescence (IRSL) was measured for a suite of identified feldspars stored for periods of up to 15 months at temperatures of ∼10°C and 100°C.

TL;DR: In this article, a series of experiments were conducted on the optical dating signal from quartz, showing the quantitative equivalence of the light sums of the optically stimulated luminescence emitted by quartz under exposure to 514.5 nm light and that of the quartz “325°C“ thermoluminescence (TL) peak.

TL;DR: In this paper, the authors used combined thermoluminescence, phosphorescence and optically stimulated luminescence (OSL) measurements to trace the movement of charge within the lattice of a geological quartz sample when exposed to light (514 nm from an Ar ion laser).

TL;DR: In this article, the infrared-stimulated luminescence (IRSL) signals in feldspars can be bleached rapidly by sunlight, and there could still be a small amount of IRSL signal remaining in sediment grains if they have experienced only relatively short sunlight exposure before deposition.

TL;DR: In this paper, the natural luminescence of quartz samples from recent (<200 yr old) glaciofluvial sediments collected from a range of distances from the snout of the Gangotri glacier in the Garhwal Himalaya, India, was measured.

TL;DR: In this article, a single aliquot technique was applied to single grains of K-feldspar extracted from a well-dated late-glacial marine sediment sample for which standard luminescence dating yielded ages that were in excess of the expected age.

TL;DR: In this paper, an anomalous fading of TL, OSL and IRSL has been observed in many samples of feldspars and attributed to the tunnel effect, and the authors proposed models to relate fading with disorder in crystals.

TL;DR: Examination of recent uses of the pre-dose technique including current research problems and wider implications of the results of pre- dose studies, in particular the study of the effect in minerals other than quartz are examined.

TL;DR: In this paper, the authors employ a method for generating dose-response data artificially in which each response is computed as the sum of a saturating exponential function and a random error, which is used to check two computing strategies, straight line conversion and simplex procedure, and investigate the optimal distribution of data points, and the role of the selection of correct weights for the fitting of the data sets.

TL;DR: In this article, a new scanning monochromator was designed to investigate the wavelength-resolved luminescence excitation and emission characteristics of quartz and feldspar samples.

TL;DR: In this article, it has been shown that the recombination dynamics of irradiated feldspars consist of a complex series of continua and line components, presumed to be associated with distinct charge transport processes between traps and recombination sites.

TL;DR: In this article, the authors proposed quantitative methods to characterize the nonlinearities in the dose dependence of thermoluminescence (TL) and suggested the use of two different nonlinearity indices, depending upon how one wishes to describe the non-linearity.

TL;DR: In this paper, the results of excitation spectra obtained from a series of irradiated feldspar and mica samples stimulated from 450 to 1200 nm using a scanning spectrometer were discussed.

TL;DR: In this article, the effect of radioactive disequilibria on luminescence dating of archaeological ceramics and some special types of sediments is discussed for several examples and compared with dose rate evaluation.

TL;DR: In this paper, the authors explored the timing of 110°C thermoluminescence and optically stimulated luminescence sensitivity changes using a natural (aeolian) quartz sample from Australia that was previously found to exhibit marked dose-dependent sensitivity change.

TL;DR: In this paper, the spectral properties of infrared-stimulated luminescence (IRSL) from a sample of potassium feldspar at low temperatures are presented. But no substantial differences were observed in the form of the decay curves at each temperature.

TL;DR: The intrinsic defect structure of quartz is sensitive to heat treatments, and this is reflected in changes in TL sensitivity and also the relative intensity of the component glow peaks as mentioned in this paper, and it is also known that even for the same crystal, there can be changes in the luminescence spectra.

TL;DR: In this paper, the seasonal variability of soil-gas radon concentration in an area which has various geological conditions but similar climate was investigated, and the results show several different patterns of seasonal variations, but all of which can be largely attributed to the water-saturation and moisture-retention characteristics of the shallow part of the soil.

TL;DR: In this article, the TL properties were investigated using both an IPDA (Intersified Photo-Diode Array) spectrometric system and a TLCI (Thermoluminescence Colour Image) method after thermal annealing treatment at several temperatures.

TL;DR: In this article, it is shown that the glow peaks of calcite, Iceland Spar and synthetic CaCO3 are consistent with a more complex set of transitions, including those from upper levels down to other excited states.

TL;DR: In this article, the optical excitation of trapped charges has been studied by stimulating them with photons of energies from 1.8 to 2.7 eV and measuring the resulting luminescence at higher photon energies.

TL;DR: In this paper, a new method for the analysis of high precision pulse annealing data obtained using IRSL measurements on potassium feldstars using a Riso reader is described.

TL;DR: In this article, an optical dating study of some quartzose sediments from northern and southern Australia, north Africa and north-western Europe has revealed that palaeodose (P ) underestimates of 10-40% are obtained when an extended-duration preheat of 160°C for 16 h is used.

TL;DR: In this paper, the effects of different methods of reduction of the IRSL signal have been investigated by subjecting potassium-rich feldspars extracted from modern dune sand from Ynyslas, on the Dyfi Estuary in Wales, to repeated cycles of removal of the luminescence signal and beta irradiation.

TL;DR: In this article, the thermoluminescence of quartz sampled at various depths in the KTB-drill hole was studied and the trapping parameters, such as activation energy, frequency factor and kinetic order, were determined by different methods: peak shift with heating rate; initial rise; peak shape; isothermal decay.

TL;DR: In this article, a TL/OSL-spectrometer has been built at the Freiberg Luminescence Dating Laboratory, which detects luminescence over a range of 200-800 nm simultaneously with a grating spectrograph and an attached liquid-nitrogen cooled CCD-array.

TL;DR: In this paper, the crystal structure of feldspar plays an important role in determining the energy positions at which optically stimulated luminescence transitions can occur, their thermo-optical behaviour, the electrical transport properties of charge in the conduction and valence bands, and the time decay characteristics of the luminecence.

TL;DR: In this paper, the authors report measurements of three-dimensional thermoluminescence emission spectra of samples of geological quartz, derived from Australian sediments, and show that the peaks of particular practical interest for sediment dating, viz. the 110°C peak, used for pre-dose dating and the peak at 325°C, which is of significant for partial and selective bleach techniques and for optically stimulated luminescence (OSL) dating, do not emit at the same wavelength.