scholarly journals Single-Grain Quartz OSL Characteristics: Testing for Correlations within and between Sites in Asia, Europe and Africa

2019 ◽  
Vol 3 (1) ◽  
pp. 2 ◽  
Author(s):  
Yue Hu ◽  
Bo Li ◽  
Zenobia Jacobs
Keyword(s):  
Growth Curve ◽  
Response Curve ◽  
Decay Curve ◽  
Optically Stimulated Luminescence ◽  
Curve Shape ◽  
Sensitivity Change ◽  
Single Grain ◽  
Distinctive Difference ◽  
Brightness Decay ◽  
Quartz Grains

We studied the characteristics of the optically stimulated luminescence (OSL) signal of single-grain quartz from three sites in China, Italy, and Libya, including the brightness, decay curve and dose response curve (DRC) shapes, recuperation, and reproducibility. We demonstrate the large variation in OSL behaviors for individual quartz grains of different samples from different regions, and show that recuperation, sensitivity change, and reproducibility are independent of the brightness and decay curve shape of the OSL signals. The single-grain DRCs can be divided into at least eight groups with different characteristic saturation doses (D0), and a standardized growth curve (SGC) can be established for each of the DRC groups. There is no distinctive difference in the shape of OSL decay curves among different DRC groups, but samples from different regions have a difference in the OSL sensitivities and decay shapes for different groups. Many of the quartz grains have low D0 values (30–50 Gy), and more than 99% of the grains have D0 values of <200 Gy. Our results raise caution against the dating of samples with equivalent dose values higher than 100 Gy, if there are many low-D0 and ‘saturated’ grains.

Luminescence and Radiocarbon Dating of Mortars at Milano-Bicocca Laboratories

Radiocarbon ◽  
2020 ◽  
Vol 62 (3) ◽  
pp. 657-666 ◽  
Author(s):  
Laura Panzeri ◽  
Francesco Maspero ◽  
Anna Galli ◽  
Emanuela Sibilia ◽  
Marco Martini
Keyword(s):  
Statistical Approach ◽  
Optically Stimulated Luminescence ◽  
Raw Material ◽  
Historical Structures ◽  
Minimum Age ◽  
Age Model ◽  
Single Grain ◽  
Sample Age ◽  
Quartz Grains ◽  
Selection Of

ABSTRACTThis work shows the results of optically stimulated luminescence (OSL) and radiocarbon (14C) dating applied to mortars of historical structures in northern Italy. All the results are compared with archaeological evidence and thermoluminescence (TL) dating of bricks. The main issue for OSL mortar dating is that the quartz grains contained in the mortar may be only partially bleached, leading to an overestimation of the sample age. In order to identify the best protocol to apply, both multi-grain (MG) and single grain (SG) methods were used. The minimum age model (MAM) statistical approach was applied to refine their accuracy. However, the identification of the bleached grains is not always successful, indicating that further investigations are needed to develop suitable dating protocol. For the 14C technique, a crucial aspect is the selection of anthropogenic calcite. In this work the mortars were treated using a Cryosonic method to select anthropogenic calcite from raw material, and the obtained powder was sieved to select the finer fraction. Unfortunately, only in two cases an acceptable amount of sample could be obtained. All the fractions were dated via accelerator mass spectrometry (AMS), and the results compared with independently obtained dates. The results show that the execution of the dating analysis requires previous characterizations to assess the nature of the mortar components and avoid unusable fractions.

scholarly journals Towards an improvement of optically stimulated luminescence (OSL) age uncertainties: modelling OSL ages with systematic errors, stratigraphic constraints and radiocarbon ages using the R package BayLum

Geochronology ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 229-245
Author(s):  
Guillaume Guérin ◽  
Christelle Lahaye ◽  
Maryam Heydari ◽  
Martin Autzen ◽  
Jan-Pieter Buylaert ◽  
...  
Keyword(s):  
R Package ◽  
Systematic Errors ◽  
Covariance Matrices ◽  
Optically Stimulated Luminescence ◽  
Osl Dating ◽  
Dose Rates ◽  
Determination Procedure ◽  
Single Grain ◽  
Measurement Uncertainties ◽  
Osl Age

Abstract. Statistical analysis has become increasingly important in optically stimulated luminescence (OSL) dating since it has become possible to measure signals at the single-grain scale. The accuracy of large chronological datasets can benefit from the inclusion, in chronological modelling, of stratigraphic constraints and shared systematic errors. Recently, a number of Bayesian models have been developed for OSL age calculation; the R package “BayLum” presented herein allows different models of this type to be implemented, particularly for samples in stratigraphic order which share systematic errors. We first show how to introduce stratigraphic constraints in BayLum; then, we focus on the construction, based on measurement uncertainties, of dose covariance matrices to account for systematic errors specific to OSL dating. The nature (systematic versus random) of errors affecting OSL ages is discussed, based – as an example – on the dose rate determination procedure at the IRAMAT-CRP2A laboratory (Bordeaux). The effects of the stratigraphic constraints and dose covariance matrices are illustrated on example datasets. In particular, the benefit of combining the modelling of systematic errors with independent ages, unaffected by these errors, is demonstrated. Finally, we discuss other common ways of estimating dose rates and how they may be taken into account in the covariance matrix by other potential users and laboratories. Test datasets are provided as a Supplement to the reader, together with an R markdown tutorial allowing the reproduction of all calculations and figures presented in this study.

Optical dating of late Quaternary carbonate sequences of Saurashtra, western India

2017 ◽  
Vol 87 (1) ◽  
pp. 133-150 ◽  
Author(s):  
Komal Sharma ◽  
Nilesh Bhatt ◽  
Anil Dutt Shukla ◽  
Dae-Kyo Cheong ◽  
Ashok Kumar Singhvi
Keyword(s):  
Late Quaternary ◽  
Optically Stimulated Luminescence ◽  
Western India ◽  
Carbonate Sediments ◽  
Sampling Strategies ◽  
Aeolian Processes ◽  
Saurashtra Coast ◽  
Recent Deposition ◽  
Quartz Grains ◽  
Carbonate Deposits

AbstractBioclastic carbonate deposits that formed because of a combination of nearshore marine, fluvial, and aeolian processes, occur along the Saurashtra coast and in the adjacent interior regions of western India. Whether these carbonates formed by marine or aeolian processes has been debated for many decades. The presence of these deposits inland poses questions as to whether they are climate controlled or attributable to postdepositional tectonic uplift. In particular, the debate centres on chronologic issues including (1) appropriate sampling strategies and (2) the use of 230Th/234U and 14C ages on the bulk carbonates. Using traces (<1%) of quartz grains trapped in carbonate matrices, optically stimulated luminescence (OSL) dating of quartz grains, deposited along with the carbonate grains, provides ages for the most recent deposition events. The OSL ages range from >165 to 44 ka for the shell limestones, 75–17 ka for the fluvially reworked sheet deposits, and 80–11 ka for miliolites deposited by aeolian processes. These are younger than the 230Th/234U and 14C ages and suggest that the inland carbonate deposits were reworked from older carbonate sediments that were transported during more arid phases.

Study of dosimetric characteristics of a commercial optically stimulated luminescence system

2017 ◽  
Vol 16 (4) ◽  
pp. 461-475 ◽  
Author(s):  
Gourav K. Jain ◽  
Arun Chougule ◽  
Ananth Kaliyamoorthy ◽  
Suresh K. Akula
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Light Exposure ◽  
Dose Range ◽  
Optically Stimulated Luminescence ◽  
Dose Response Curve ◽  
Field Size ◽  
In Vivo Dosimetry ◽  
Detector Response

AbstractBackgroundOptically stimulated luminescence dosimeters (OSLDs) have a number of advantages in radiation dosimetry making them an excellent dosimeter for in vivo dosimetry. The study aimed to study the dosimetric characteristics of a commercial optically stimulated luminescence (OSL) system by Landauer Inc., before using it for routine clinical practice for in vivo dosimetry in radiotherapy. Further, this study also aimed to investigate the cause of variability found in the literature in a few dosimetric parameters of carbon-doped aluminium oxide (Al2O3:C).Materials and methodsThe commercial OSLD system uses Al2O3:C nanoDotTM as an active radiation detector and InLightTM microStar® as a readout assembly. Inter-detector response, energy, dose rate, field size and depth dependency of the detector response were evaluated for all available clinical range of photon beam energies in radiotherapy.ResultsInter-detector variation in OSLD response was found within 3·44%. After single light exposure for the OSL readout, detector reading decreased by 0·29% per reading. The dose linearity was investigated between dose range 50–400 cGy. The dose response curve was found to be linear until 250 cGy, after this dose, the dose response curve was found to be supra-linear in nature. OSLD response was found to be energy independent for Co60 to 10 MV photon energies.ConclusionsThe cause of variability found in the literature for some dosimetric characteristics of Al2O3:C is due to the difference in general geometry, construction of dosimeter, geometric condition of irradiation, phantom material and geometry, beam energy. In addition, the irradiation history of detector used and difference in readout methodologies had varying degree of uncertainties in measurements. However, the large surface area of the detector placed in the phantom with sufficient build-up and backscatter irradiated perpendicularly to incident radiation in Co60 beam is a good method of choice for the calibration of a dosimeter. Understanding the OSLD response with all dosimetric parameters may help us in estimation of accurate dose delivered to patient during radiotherapy treatment.

scholarly journals Dating mortar by optically stimulated luminescence: A feasibility study

2011 ◽  
Vol 38 (1) ◽  
pp. 42-49 ◽  
Author(s):  
Christian Goedicke
Keyword(s):  
Dose Rate ◽  
Short Range ◽  
Optically Stimulated Luminescence ◽  
Radioactive Equilibrium ◽  
Lime Mortar ◽  
Modulation Techniques ◽  
Single Grain ◽  
Optical Bleaching ◽  
Number Of Publications

AbstractQuartz is the datable component in mortar. Although its luminescence properties are very well studied, the problem of mortar dating arises from a low level of optical bleaching. In order to reduce the time consuming efforts for dating lime mortar in monuments by optically stimulated luminescence, we investigated the most suitable methods of dose and dose rate determination, and we explored tests which are suitable to predict the datability of a given material. Reverting to the large number of publications on sedimentary partially bleached quartz we found linear modulation techniques especially useful, equally we also recommend the determination of the level of optical depletion before starting analyses. Single grain analysis is regarded as an ultimate but infallible tool to date very poorly bleached quartz from mortar. Dose rate measurements need to take into account the radioactive equilibrium of the uranium decay and the short range inhomogeneity of the environmental gamma radiation field: gamma spectrometry and on-site TLD measurements are best suited.

Effects of thermal treatment on the growth curve shape for OSL of quartz extracted from Chinese loess

2008 ◽  
Vol 43 (2-6) ◽  
pp. 763-766 ◽  
Author(s):  
ZhongPing Lai ◽  
Helmut Brückner ◽  
Alexander Fülling ◽  
Ludwig Zöller
Keyword(s):  
Thermal Treatment ◽  
Growth Curve ◽  
Curve Shape ◽  
Chinese Loess

scholarly journals Constraints on the precision of SAR in equivalent dose estimations close to saturation in quartz

2011 ◽  
Vol 38 (4) ◽  
pp. 413-423 ◽  
Author(s):  
Constantin Athanassas
Keyword(s):  
Growth Curve ◽  
Late Quaternary ◽  
Equivalent Dose ◽  
Curve Shape ◽  
Large Scatter ◽  
Dose Estimation ◽  
Quaternary Sediments ◽  
The South ◽  
Of Greece

Abstract Difficulties in evaluating accurate equivalent doses for Late Quaternary sediments from the south coasts of Greece arose in the course of SAR measurements. Large scatter among apparent equivalent doses perplexed the evaluation of accurate mean estimates in circumstances where very large doses were involved. Besides, dose recovery experiments revealed that when intersection of the natural signal occurs onto the saturating segment of the growth curve, a distinct relationship between De and growth curve shape occurs. At very low slope angles, SAR tends to overestimate the recovered dose. The mechanism which controls the spread in equivalent dose estimation is investigated.

Luminescence sensitivities of quartz grains from eolian deposits in northern China and their implications for provenance

2011 ◽  
Vol 76 (2) ◽  
pp. 181-189 ◽  
Author(s):  
Tongyan Lü ◽  
Jimin Sun
Keyword(s):  
Regional Difference ◽  
Northern China ◽  
Spatial Variations ◽  
Optically Stimulated Luminescence ◽  
Red Clay ◽  
Rock Types ◽  
Eolian Deposits ◽  
Source Materials ◽  
Quartz Grains

AbstractThe thermoluminescence (TL) and optically stimulated luminescence (OSL) sensitivities of quartz grains from deserts and loess–red clay sequences are used to trace eolian provenances in northern China. Our results indicate that the 110°C TL peak and OSL sensitivities of quartz grains show differences among Chinese deserts, which can be subdivided into four groups according to the spatial variations of luminescence sensitivities. Such differences are related mostly to the regional difference in rock types of mountains surrounding or adjacent to the deserts. We also examine the possible provenance changes between the Quaternary loess and the Tertiary eolian red clay, and the results indicate that the luminescence sensitivity of Tertiary red clay is higher than that of Quaternary loess (L1, L15, and L33), implying source materials of the eolian deposits changed relative to those of the Quaternary.

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