{"type": "FeatureCollection", "features": [{"id": "10.1016/j.radmeas.2019.106221", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-04T16:16:52Z", "type": "Journal Article", "created": "2019-11-19", "title": "Bleaching studies on Al-hole ([AlO4/h]0) electron spin resonance (ESR) signal in sedimentary quartz", "description": "Abstract   Electron spin resonance (ESR) dating of sediments using quartz is most commonly used for older sediments (>100 ka), since large residuals render the ESR signal unsuitable for dating young sediments. The multiple-centre approach (utilising both Ti and [AlO4/h]0 signals) is usually used to test the resetting of the signals used for ESR dating. Here we work towards a better understanding of, and correction for, the residual signal in ESR samples of sedimentary quartz. We undertook multiple-centre ESR measurements using quartz [AlO4/h]0 and Ti signals on young aeolian samples of different grain sizes which have been independently dated using optically stimulated luminescence (OSL). Our results demonstrate that [AlO4/h]0 signal yields residuals indicating equivalent doses of about 500\u00a0Gy, substantially older than expected for the known OSL equivalent doses in the range of 8\u201337\u00a0Gy. The decay of [AlO4/h]0 signal as function of bleaching time can be represented by an exponential function. We investigate the dependence of the residual magnitude of the ESR signal as a function of the previous given dose and observe an exponential increase in the residual signal with dose. Such observations are consistent with the results of luminescence process modelling conducted for a model comprising two luminescence centres and several traps, one of which is a so-called deep disconnected trap that cannot be emptied during optical stimulation. We propose that bleaching occurs through an electron-hole recombination process with electrons released from optically sensitive traps. In addition to our new insights into the bleaching mechanisms of the [AlO4/h]0 ESR signal, we discuss the implications for the procedures used for performing residual dose corrections in ESR dating. We recommend that modern analogues be used in addition to laboratory-bleached samples when performing residual dose corrections.", "keywords": ["ESR dating", "Sedimentary quartz", "03 medical and health sciences", "0302 clinical medicine", "Residual", "Sedimentary quartz ESR dating[AlO4/h]0 Residual Bleaching Modelling", "[AlO4/h]0", "Bleaching", "01 natural sciences", "Modelling", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://doi.org/10.1016/j.radmeas.2019.106221"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Radiation%20Measurements", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.radmeas.2019.106221", "name": "item", "description": "10.1016/j.radmeas.2019.106221", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.radmeas.2019.106221"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-01-01T00:00:00Z"}}, {"id": "10.1016/j.radmeas.2019.106187", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-04T16:16:52Z", "type": "Journal Article", "created": "2019-09-16", "title": "Phenomenological model of aluminium-hole ([AlO4/h+]0) defect formation in sedimentary quartz upon room temperature irradiation: electron spin resonance (ESR) study", "description": "Abstract   The mechanism governing the production of the paramagnetic [AlO4/h+]0 centres (denoted also as Al-hole or Al-h) in quartz as a function of given dose is of great importance in electron spin resonance (ESR) dating, as the analytical function used to characterise the evolution of this centre with accumulated dose is used to derive the equivalent dose by extrapolation to the abscissa-axis. The single saturating exponential model fails to accurately represent the dose response curve especially at high doses, and consequently, empirical functions, such as a saturating exponential plus a linear term, are widely used in the dating community. Herein, a physical phenomenological model is presented to describe the Al-hole formation under gamma irradiation in sedimentary quartz. Based on previous studies it is known that the Al-hole centre is formed via the dissociation of the Al centres compensated with alkali ions [AlO4/M+]0 (generally denoted as Al-M) where M+ could be Li+, Na+ or K+, as well as by the dissociation of Al compensated with hydrogen ions [AlO4/H+]0, (denoted as Al\u2013H). When irradiation moves interstitial alkali ions away from the aluminium ions, they can be replaced by H+ ions beside the conversion to Al-hole centres. By assuming that the rate of the dissociation process is proportional to the concentration of the defects themselves, a sum of saturating exponential functions is obtained for describing the growth of Al-hole with dose. The model is applied on data obtained on sedimentary quartz specimens of different origins for describing the dose response of the paramagnetic Al-hole ESR signal. We are showing that the signal of Al-hole does not reach full saturation at doses even as high as 100\u00a0kGy and can it be well represented by two exponential components as predicted by the model. As such, the additional linear term reported by other works when describing the dose response is just a first order approximation of one of the saturating exponential functions.", "keywords": ["03 medical and health sciences", "0302 clinical medicine", "ESR dating Al-hole centres ([AlO4/h+]0)Production mechanism Dose response curve", "01 natural sciences", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://doi.org/10.1016/j.radmeas.2019.106187"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Radiation%20Measurements", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.radmeas.2019.106187", "name": "item", "description": "10.1016/j.radmeas.2019.106187", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.radmeas.2019.106187"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-01-01T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=ESR+dating&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=ESR+dating&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=ESR+dating&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=ESR+dating&offset=2", "hreflang": "en-US"}], "numberMatched": 2, "numberReturned": 2, "distributedFeatures": [], "timeStamp": "2026-04-05T08:59:32.726953Z"}