{"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": "10.5281/zenodo.3548796", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-04T16:23:47Z", "type": "Journal Article", "created": "2021-01-30", "title": "On the dose dependence prior and after stimulation with visible light of E' and Al-hole centres in sedimentary quartz: correlation and mechanisms", "description": "E\u2019 and Al-hole centres are some of the most common and abundant paramagnetic defects in sedimentary quartz. Here we investigate the dose dependence of these defects before and after exposure to light by electron spin resonance (ESR). Unlike the Al-hole centre, known to have only radiation-induced formation mechanisms, the E\u2019 seems to possess a response to gamma dose characterised by predominantly radiation-induced annihilation at lower doses (about 1000 Gy) and a predominantly radiation-induced formation at higher doses, at least in our investigated dose range (up to 40 kGy). We propose these dose response mechanisms to be governed by electron trapping by E\u2019 itself and by hole trapping by the oxygen deficiency centre (ODC), known to be the main precursor of E\u2019. We show that the ESR signals of both defects are linearly correlated during their formation as well as during their dissociation under both irradiation and sunlight exposure. We further show that there is a clear correlation between the light sensitive Al-hole centres (also known as the Al-hole bleachable part), and the amount of E\u2019 produced after prolonged light exposure. This indicates a correlation between the holes released from Al-hole and those trapped by one of the two electrons in the ODCs producing E\u2019. As such, the origin of the unbleachable part of the Al-hole signal resides in the availability of oxygen deficiency centres which are also dependent on the accumulated gamma dose.", "keywords": ["03 medical and health sciences", "0302 clinical medicine", "electron spin resonance; E' centres; Al-hole centres; gamma dose response; mechanisms; bleaching; correlation", "01 natural sciences", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://doi.org/10.5281/zenodo.3548796"}, {"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": "10.5281/zenodo.3548796", "name": "item", "description": "10.5281/zenodo.3548796", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.3548796"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-02-01T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Bleaching&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=Bleaching&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=Bleaching&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Bleaching&offset=2", "hreflang": "en-US"}], "numberMatched": 2, "numberReturned": 2, "distributedFeatures": [], "timeStamp": "2026-04-05T08:58:04.997097Z"}