ORCID Profile
0000-0002-8942-7566
Current Organisations
Technical University of Denmark
,
Danmarks Tekniske Universitet
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 12-2018
Publisher: Wiley
Date: 18-05-2016
DOI: 10.1111/BOR.12180
Publisher: Elsevier BV
Date: 09-2012
Publisher: Walter de Gruyter GmbH
Date: 28-01-2011
DOI: 10.2478/S13386-011-0003-Z
Abstract: Recent work has identified IR stimulated luminescence signals at elevated temperature from both potassium- and sodium-rich feldspars that have much lower anomalous fading rates than the conventional signal measured using IR stimulation at 50°C. This paper examines the stability of these signals for potassium-rich sedimentary feldspars. We show that the natural post-IR IRSL (pIRIR) signal from a 3.6 Ma old s le is in apparent saturation on a laboratory generated dose response curve, i.e. it does not show detectable fading in nature although a low fading rate is observed on laboratory time scales. We show that the pIRIR signal has a greater thermal stability than the IRSL signal and that the trend in increasing thermal stability is mirrored by a decreasing fading rate. We also investigate the effect of preheat temperature and IR stimulation power on the decay shape and conclude that the data can be explained in terms of either a single- or multiple-trap model. We present evidence that may suggest that at least part of pIRIR signal is derived from a high temperature trap (∼550°C thermoluminescence (TL) peak), although again the data can also be explained in terms of a single-trap model. Finally, we present dose response curves and characteristic curvature constants (D0) values for various IRSL signals and conclude that the more stable signals saturate more quickly than the less stable signals and that the initial and final signals saturate at approximately the same level.
Publisher: American Geophysical Union (AGU)
Date: 09-2012
DOI: 10.1029/2012JB009383
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 03-2018
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 10-2021
Publisher: Walter de Gruyter GmbH
Date: 2016
Abstract: Optically stimulated luminescence (OSL) is increasingly applied to the dating of rock surfaces. There is at present no practical way of separating pure minerals (quartz and feldspar) from hard rocks for OSL measurement without losing the grain-size dependent dosimetric information and there is little information about the performance of the single-aliquot regeneration-dose (SAR) measurement protocol on the post-infrared infrared stimulated luminescence (pIRIR) signals from rock slices. The latter is investigated here. Our data indicate that there is a systematic increase in dose response curve saturation (or D o ) with test dose size when the regeneration doses are first given in increasing order, and then decreasing order. This trend disappears if these orders are reversed. The reproducibility of dose response curves is dependent on the size of the test dose (poorer for small test dose). For rock slices given a saturation dose in the laboratory, it is observed that the sensitivity corrected pIRIR 290 signal lies close to saturation level of the dose response curve, for first IR stimulation at temperatures between 50 and 250°C. However, the pIRIR 290 signal from naturally saturated slices lies close to the laboratory saturation levels only for higher first IR stimulation temperatures e.g. 200°C or 250°C. Our data confirm earlier suggestions based on sand-grain measurements that, for older s les, accurate measurements close to saturation require that a higher first IR temperature is used.
Publisher: Springer Science and Business Media LLC
Date: 28-11-2017
DOI: 10.1038/S41467-017-01643-9
Abstract: Urbanism in the Bronze-age Indus Civilisation (~4.6–3.9 thousand years before the present, ka) has been linked to water resources provided by large Himalayan river systems, although the largest concentrations of urban-scale Indus settlements are located far from extant Himalayan rivers. Here we analyse the sedimentary architecture, chronology and provenance of a major palaeochannel associated with many of these settlements. We show that the palaeochannel is a former course of the Sutlej River, the third largest of the present-day Himalayan rivers. Using optically stimulated luminescence dating of sand grains, we demonstrate that flow of the Sutlej in this course terminated considerably earlier than Indus occupation, with ersion to its present course complete shortly after ~8 ka. Indus urban settlements thus developed along an abandoned river valley rather than an active Himalayan river. Confinement of the Sutlej to its present incised course after ~8 ka likely reduced its propensity to re-route frequently thus enabling long-term stability for Indus settlements sited along the relict palaeochannel.
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 03-2021
Publisher: Walter de Gruyter GmbH
Date: 19-06-2011
DOI: 10.2478/S13386-011-0029-2
Abstract: There are many ex les of buried rock surfaces whose age is of interest to geologists and archaeologists. Luminescence dating is a potential method which can be applied to dating such surfaces as part of a research project which aims to develop such an approach, the degree of resetting of OSL signals in grains and slices from five different cobbles/boulders collected from a modern beach is investigated. All the rock surfaces are presumed to have been exposed to daylight for a prolonged period of time (weeks to years). Feldspar was identified as the preferred dosimeter because quartz extracts were insensitive. Dose recovery tests using solar simulator and IR diodes on both K-feldspar grains and solid slices taken from the inner parts of the rocks are discussed. Preheat plateau results using surface grains and slices show that significant thermal transfer in naturally bleached s les can be avoided by keeping preheat temperatures low. Equivalent doses from surface K-feldspar grains were highly scattered and much larger than expected (0.02 Gy to Gy), while solid surface slices gave more reproducible small doses (mean = 0.17±0.02 Gy, n = 32). Neither crushing nor partial bleaching were found to be responsible for the large scattered doses from grains, nor did the inevitable contribution from Na-feldspar to the signal from solid slices explain the improved reproducibility in the slices. By modelling the increase of luminescence signal with distance into the rock surface, attenuation factors were derived for two s les. These indicate that, for instance, bleaching at a depth of 2 mm into these s les occurs at about ∼28% of the rate at the surface. We conclude that it should be possible to derive meaningful burial doses of Gy from such cobbles younger s les would probably require a correction for incomplete bleaching.
Publisher: Elsevier BV
Date: 05-2011
Publisher: Elsevier BV
Date: 02-2019
Publisher: IOP Publishing
Date: 23-07-2010
DOI: 10.1088/0022-3727/43/32/325502
Abstract: A time-resolved optically stimulated exo-electron (TR-OSE) measurement system has been developed using a Photon Timer attached to a gas-flow semi-proportional pancake electron detector within a Risø TL/OSL reader. The decay rate of the exo-electron emission after the stimulation pulse depends on the probability of (1) escape of electrons into the detector gas from the conduction band by overcoming the work function of the material and (2) thermalization of electrons in the conduction band, and subsequent re-trapping/recombination. Thus, we expect the exo-electron signal to reflect the instantaneous electron concentration in the conduction band. In this study, TR-OSE and time-resolved optically stimulated luminescence (TR-OSL) were measured for the first time using quartz, K-feldspar and NaCl by stimulating the s les using pulsed blue LEDs at different temperatures between 50 and 250 °C after beta irradiation and preheating to 280 °C. The majority of TR-OSE signals from all the s les decayed much faster than TR-OSL signals irrespective of the stimulation temperatures. This suggests that the lifetime of OSL in these dosimeters arises mainly from the relaxation of an excited state of the recombination centre, rather than from residence time of an electron in the conduction band.
Publisher: Elsevier BV
Date: 04-2013
Publisher: Copernicus GmbH
Date: 28-04-2021
DOI: 10.5194/GCHRON-3-229-2021
Abstract: 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 s les 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 ex le – 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 ex le 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.
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 10-2008
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 05-2009
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 05-2009
Publisher: Elsevier BV
Date: 07-2018
Publisher: Elsevier BV
Date: 07-2012
Publisher: Elsevier BV
Date: 11-2022
Publisher: Elsevier BV
Date: 12-2003
Publisher: Elsevier BV
Date: 03-2015
Publisher: Elsevier BV
Date: 04-2012
Publisher: Elsevier BV
Date: 05-2009
Publisher: Elsevier BV
Date: 06-2011
Publisher: Elsevier BV
Date: 08-2010
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 06-2011
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 05-2010
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 02-2016
Publisher: Elsevier BV
Date: 05-2009
Publisher: Elsevier BV
Date: 06-2015
Publisher: Elsevier BV
Date: 12-2013
Publisher: Wiley
Date: 03-2012
Publisher: Elsevier BV
Date: 02-2017
Publisher: Elsevier BV
Date: 12-2023
Publisher: Elsevier BV
Date: 11-2017
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 04-2013
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 04-2017
Publisher: Elsevier BV
Date: 05-2009
Publisher: Elsevier BV
Date: 11-2017
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 08-2017
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 09-2014
Publisher: Elsevier BV
Date: 10-2022
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 08-2012
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 04-2015
Publisher: Elsevier BV
Date: 03-2009
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 10-2011
No related grants have been discovered for Mayank Jain.