Christopher Ian Burbidge

A Bayesian approach to the evaluation of equivalent doses in sediment mixtures for luminescence dating

The optically stimulated luminescence from minerals is proving to be a very useful dating technique in archaeology and physical geography. In this work we study the analysis of the relevant data from a Bayesian viewpoint, comparing some simple age and noise models.

Combined gamma and beta dosimetry, using Al2O3:C, for in situ measurements on a sequence of archaeological deposits

Abstract Single crystal chips of Al 2 O 3 :C (TLD500) were evaluated and employed for measurements of combined gamma, beta, and cosmic dose-rate. A regenerative dose optically stimulated luminescence (OSL) measurement procedure is described, using the closed source of a Ris o reader for irradiation. The reproducibility of these measurements was assessed for both irradiation within the reader, and during field deployment. Combined dose-rate measurements using the chips were corrected for beta attenuation by comparison with independent dose-rate measurements. Dosimeters were buried for up to 3 weeks in the field, providing parallel measurements of in situ combined dose-rate for 79 OSL samples.

The potential for dating the Old Scatness site, Shetland, by optically stimulated luminescence

A series of deposits from the agricultural infield of the multiperiod settlement mound, Old Scatness, were investigated for their potential to yield optically stimulated luminescence dates. Luminescence properties of quartz grains were found to vary through the sequence, but dates were successfully obtained from five deposits, including anthropogenic soils, windblown sands and sands within midden deposits. Single-aliquot equivalent dose measurement was found to be the most appropriate method for dating the deposits. The OSL dates obtained accorded well with the dates provided by archaeological evidence and included the post-medieval, Iron Age, Bronze Age and Neolithic periods of Shetland, while a substantial midden was dated to the Bronze/Iron Age transition.

Overview of physical dosimetry methods for triage application integrated in the new European network RENEB.

Abstract Purpose: In the EC-funded project RENEB (Realizing the European Network in Biodosimetry), physical methods applied to fortuitous dosimetric materials are used to complement biological dosimetry, to increase dose assessment capacity for large-scale radiation/nuclear accidents. This paper describes the work performed to implement Optically Stimulated Luminescence (OSL) and Electron Paramagnetic Resonance (EPR) dosimetry techniques. Materials and methods: OSL is applied to electronic components and EPR to touch-screen glass from mobile phones. To implement these new approaches, several blind tests and inter-laboratory comparisons (ILC) were organized for each assay. Results: OSL systems have shown good performances. EPR systems also show good performance in controlled conditions, but ILC have also demonstrated that post-irradiation exposure to sunlight increases the complexity of the EPR signal analysis. Conclusions: Physically-based dosimetry techniques present high capacity, new possibilities for accident dosimetry, especially in the case of large-scale events. Some of the techniques applied can be considered as operational (e.g. OSL on Surface Mounting Devices [SMD]) and provide a large increase of measurement capacity for existing networks. Other techniques and devices currently undergoing validation or development in Europe could lead to considerable increases in the capacity of the RENEB accident dosimetry network.

Facets of Luminescence for Dating

ABSTRACT The aim of this article is to introduce luminescence dating and relate it to luminescence and Raman spectroscopy of minerals. The physical bases of luminescence signals used in dating and their relationships to other radiation-induced luminescence and Raman signals are briefly reviewed. The manner in which these signals are applied to evaluate luminescence ages is described. Archaeological and geological case studies from the authors experience are used to illustrate potentialities and issues related to different contexts, techniques, and materials.

RENEB accident simulation exercise

Abstract Purpose: The RENEB accident exercise was carried out in order to train the RENEB participants in coordinating and managing potentially large data sets that would be generated in case of a major radiological event. Materials and methods: Each participant was offered the possibility to activate the network by sending an alerting email about a simulated radiation emergency. The same participant had to collect, compile and report capacity, triage categorization and exposure scenario results obtained from all other participants. The exercise was performed over 27 weeks and involved the network consisting of 28 institutes: 21 RENEB members, four candidates and three non-RENEB partners. Results: The duration of a single exercise never exceeded 10 days, while the response from the assisting laboratories never came later than within half a day. During each week of the exercise, around 4500 samples were reported by all service laboratories (SL) to be examined and 54 scenarios were coherently estimated by all laboratories (the standard deviation from the mean of all SL answers for a given scenario category and a set of data was not larger than 3 patient codes). Conclusions: Each participant received training in both the role of a reference laboratory (activating the network) and of a service laboratory (responding to an activation request). The procedures in the case of radiological event were successfully established and tested.

A broadly applicable function for describing luminescence dose response

The basic form of luminescence dose response is investigated, with the aim of developing a single function to account for the appearance of linear, superlinear, sublinear, and supralinear behaviors and variations in saturation signal level and rate. A function is assembled based on the assumption of first order behavior in different major factors contributing to measured luminescence-dosimetric signals. Different versions of the function are developed for standardized and non-dose-normalized responses. Data generated using a two trap two recombination center model and experimental data for natural quartz are analyzed to compare results obtained using different signals, measurement protocols, pretreatment conditions, and radiation qualities. The function well describes a range of dose dependent behavior, including sublinear, superlinear, supralinear, and non-monotonic responses and relative response to α and β radiation, based on change in relative recombination and trapping probability affecting signals sourced from a single electron trap.

Capabilities of the RENEB network for research and large scale radiological and nuclear emergency situations

Abstract Purpose: To identify and assess, among the participants in the RENEB (Realizing the European Network of Biodosimetry) project, the emergency preparedness, response capabilities and resources that can be deployed in the event of a radiological or nuclear accident/incident affecting a large number of individuals. These capabilities include available biodosimetry techniques, infrastructure, human resources (existing trained staff), financial and organizational resources (including the role of national contact points and their articulation with other stakeholders in emergency response) as well as robust quality control/assurance systems. Materials and methods: A survey was prepared and sent to the RENEB partners in order to acquire information about the existing, operational techniques and infrastructure in the laboratories of the different RENEB countries and to assess the capacity of response in the event of radiological or nuclear accident involving mass casualties. The survey focused on several main areas: laboratory’s general information, country and staff involved in biological and physical dosimetry; retrospective assays used, the number of assays available per laboratory and other information related to biodosimetry and emergency preparedness. Following technical intercomparisons amongst RENEB members, an update of the survey was performed one year later concerning the staff and the available assays. Conclusions: The analysis of RENEB questionnaires allowed a detailed assessment of existing capacity of the RENEB network to respond to nuclear and radiological emergencies. This highlighted the key importance of international cooperation in order to guarantee an effective and timely response in the event of radiological or nuclear accidents involving a considerable number of casualties. The deployment of the scientific and technical capabilities existing within the RENEB network members seems mandatory, to help other countries with less or no capacity for biological or physical dosimetry, or countries overwhelmed in case of a radiological or nuclear accident involving a large number of individuals.

Archaeometric Contribution for Heritage Management Compositional Analysis and dating of ceramics from a Portuguese collection

Different analytical methods comprising mineralogical and chemical analysis and thermoluminescence dating were used to assess the most appropriate techniques for the characterisation and dating of a ceramic collection. This study demonstrates the complementary nature of these techniques. The materials studied consist of ceramics from the collection of the Estrada Foundation, which will form part of a future museum in Abrantes Portugal.