| 1. |
- Ainsbury, Elizabeth A., et al.
(författare)
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UNCERTAINTY ON RADIATION DOSES ESTIMATED BY BIOLOGICAL AND RETROSPECTIVE PHYSICAL METHODS
- 2018
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Ingår i: Radiation Protection Dosimetry. - : OXFORD UNIV PRESS. - 0144-8420 .- 1742-3406. ; 178:4, s. 382-404
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Tidskriftsartikel (refereegranskat)abstract
- Biological and physical retrospective dosimetry are recognised as key techniques to provide individual estimates of dose following unplanned exposures to ionising radiation. Whilst there has been a relatively large amount of recent development in the biological and physical procedures, development of statistical analysis techniques has failed to keep pace. The aim of this paper is to review the current state of the art in uncertainty analysis techniques across the EURADOS Working Group 10-Retrospective dosimetry members, to give concrete examples of implementation of the techniques recommended in the international standards, and to further promote the use of Monte Carlo techniques to support characterisation of uncertainties. It is concluded that sufficient techniques are available and in use by most laboratories for acute, whole body exposures to highly penetrating radiation, but further work will be required to ensure that statistical analysis is always wholly sufficient for the more complex exposure scenarios.
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| 2. |
- Adliene, Diana, et al.
(författare)
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Assessment of the environmental contamination with long-lived radionuclides around an operating RBMK reactor station
- 2006
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 90:1, s. 68-77
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Tidskriftsartikel (refereegranskat)abstract
- The presence of man-made gamma emitting radionuclides in the region within 32 km radius of the Ignalina NPP/Lithuania has been investigated during the period 2001-2004, prior to the closure of the first 4 the two operating RBMK 1500-type reactors. Gamma spectrometric measurements of various terrestrial and aquatic plants as well as of soil samples showed moderate environmental contamination with the fission product Cs-137 and with the neutron activation products Co-60 and Mn-54. Traces of the activation products Zn-65 and Ag-110m were found in the nearest vicinity of the NPP. Activity concentrations were inhomogeneously distributed in the area of interest. Moss and algae samples showed the highest uptake of radionuclides. In addition to the gamma spectrometric measurements, the levels of C-14 were determined in the same bio-indicator samples using accelerator mass spectrometry. (c) 2006 Elsevier Ltd. All rights reserved.
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| 3. |
- Bernhardsson, Christian, et al.
(författare)
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Assessment of effective dose to an individual carrying materials useful for radiation dosimetry by optically stimulated luminescence
- 2015
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Ingår i: Medical Physics in the Baltic States : Proceedings of the 12th International Conference on Medical Physics - Proceedings of the 12th International Conference on Medical Physics. - 1822-5721. ; , s. 48-51
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Konferensbidrag (refereegranskat)abstract
- Optically stimulated luminescence (OSL) from ordinary household salt has proven high potential for very low dose retrospective dosimetry. In the present paper other common place materials are considered and their dosimetric OSL-properties compared with household salt. The potential for assessment of the effective dose to an individual carrying such materials is investigated.
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| 4. |
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| 5. |
- Bernhardsson, Christian, et al.
(författare)
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Comparative Measurements of the External Radiation Exposure in a 137Cs Contaminated Village in Belarus Based on Optically Stimulated Luminescence in NaCl and Thermoluminescence in LiF.
- 2012
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Ingår i: Health Physics. - 1538-5159. ; 103:6, s. 740-749
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: Laboratory studies have shown that ordinary household salt (NaCl) exhibits several promising properties for retrospective dosimetry; e.g., a linear dose response and a low detection limit, down to a few mGy or even less. In an attempt to test NaCl as a dosimeter outside the laboratory, the first results from the use of NaCl as a dosimeter under normal environmental conditions are reported here. For this purpose, special dosimeter kits with NaCl and lithium fluoride (LiF) chips were designed. The dosimeter kits were positioned at different locations in a Chernobyl Cs-contaminated village in Belarus during the summers of 2008, 2009, and 2010. The results from the two luminescent detectors were also compared with those of measurements carried out with a handheld 75 cm NaI(Tl) detector and with a 8 dm high pressure ionization chamber. The radiation level in the village was inhomogeneous, and depending on the type of house and countermeasures carried out, the ambient dose rate inside and around the houses varied between 0.05 μSv h and 0.50 μSv h. Based on the different measurements, the annual external effective dose to a hypothetical adult population in the village was estimated as 1-1.5 mSv y. Detector readings from the two luminescent materials correlated relatively strongly to that of the ambient survey NaI(Tl) detector. After three repeated surveys using similar dosimeter kits for prospective dosimetry, the potential use of ordinary household salt as a complement to other techniques for retrospective dose estimations is more evident, and shortcomings of the technique have been identified.
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| 6. |
- Bernhardsson, Christian, et al.
(författare)
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Environmental radiation baseline around the Belarusian nuclear power plant – assessments in Belarus and Lithuania
- 2023
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Ingår i: Medical Physics in the Baltic States : Proceedings of the 16<sup>th</sup> International Conference on Medical Physics - Proceedings of the 16<sup>th</sup> International Conference on Medical Physics. - 1822-5721. ; , s. 121-125
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Konferensbidrag (refereegranskat)abstract
- Prior to the operation of the first Belarussian nuclear power plant (BelNPP), the baseline of the radiation environment was determined within a radius of about 30 km from BelNPP. This independent assessment was carried out during two expeditions in 2019. In 2022, a similar survey was carried out (during the initialoperation of BelNPP) on the Lithuanian side of the boarder. Here we present the overall project and some general results of the baseline assessments.
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| 7. |
- Bernhardsson, Christian, et al.
(författare)
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Household salt as a retrospective dosemeter using optically stimulated luminescence.
- 2009
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 48, s. 21-28
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to investigate the potential of a selection of household salts (NaCl) as a retrospective dosemeter for ionising radiation using optically stimulated luminescence (OSL). The OSL-response of five brands of salt to an absorbed dose in the range from 1 mGy to 9 Gy was investigated using a Risø TL/OSL-15 reader and a (60)Co beam, allowing low dose-rate irradiations. The salt was optically stimulated with blue light (lambda = 470 +/- 30 nm) at a constant stimulation power (CW-OSL) of 20 mW cm(-2). A linear dose response relationship was found in the dose range from 1 mGy to about 100 mGy and above that level, the relationship becomes moderately supra-linear, at least up to 9 Gy. Depending on the sensitivity and background signal, the minimum detectable absorbed dose (MDD) for the household salt when kept at sealed conditions varied from 0.2 to 1.0 mGy, for the household salts investigated. In addition to its widespread abundance and availability, the low MDD suggests that household salt should seriously be considered as an emergency dosemeter. However, the OSL-properties of NaCl under normal household usage need to be more properly investigated as well as the variation in sensitivity by the quality of the radiation. A further optimisation of the read-out sequence for various brands of commercially available salt may further improve the sensitivity, in terms of luminescence yield, and the signal reproducibility.
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| 8. |
- Bernhardsson, Christian, et al.
(författare)
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Household salt (NaCl) for optically stimulated luminescence dosimetry: an overview
- 2021
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Ingår i: Medical Physics in the Baltic States : Proceedings of the 15th International Conference on Medical Physics - Proceedings of the 15th International Conference on Medical Physics. - 1822-5721. ; , s. 90-94
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Konferensbidrag (refereegranskat)abstract
- This brief overview of the use of household salt (NaCl) in optically stimulated luminescence (OSL) dosimetry is focusing on the use of NaCl pellets. It is suggested that the most optimal use of household NaCl, in general prospective dosimetry, is to compress the salt grains to pellets and read the radiation induced signal using OSL rather than TL. A summary of the main OSL dosimetric properties is provided for two Swedish household salts, and compared to the OSL properties of 100 different salts from all over the world.
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| 9. |
- Bernhardsson, Christian, et al.
(författare)
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Measurements of long-term external and internal radiation exposure of inhabitants of some villages of the Bryansk region of Russia after the Chernobyl accident
- 2011
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 409:22, s. 4811-4817
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Tidskriftsartikel (refereegranskat)abstract
- A Nordic-Soviet programme was initiated in 1990 to evaluate the external and internal radiation exposure of the inhabitants of several villages in the Bryansk region of Russia. This area was one of the number of areas particularly affected by the nuclear accident at the Chernobyl Nuclear Power Plant in 1986. Measurements were carried out yearly until 1998 and after that more irregularly; in 2000, 2006 and 2008 respectively. The effective dose estimates were based on individual thermoluminescent dosemeters and on in vivo measurements of the whole body content of (137)Cs (and (134)Cs during the first years of the programme). The decrease in total effective dose during the almost 2 decade follow-up was due to a continuous decrease in the dominating external exposure and a less decreasing but highly variable exposure from internal irradiation. In 2008, the observed average effective dose (i.e. the sum of external and internal exposure) from Chernobyl (137)Cs to the residents was estimated to be 0.3mSvy(-1). This corresponds to 8% of the estimated annual dose in 1990 and to 1% of the estimated annual dose in 1986. As a mean for the population group and for the period of the present study (2006-2008), the average yearly effective dose from Chernobyl cesium was comparable to the absorbed dose obtained annually from external exposure to cosmic radiation plus internal exposure to naturally occurring radionuclides in the human body. Our data indicate that the effective dose from internal exposure is becoming increasingly important as the body burdens of Chernobyl (137)Cs are decreasing more slowly than the external exposure. However, over the years there have been large individual variations in both the external and internal effective doses, as well as differences between the villages investigated. These variations and differences are presented and discussed in this paper.
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| 10. |
- Bernhardsson, Christian, et al.
(författare)
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OSL in Household Salt (NaCl) for Environmental, Occupational and Medical Dosimetry
- 2009
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Ingår i: Medical Physics In The Baltic States: Proceedings Of The 7th International Conference On Medical Physics. - 1822-5721. ; , s. 65-68
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Konferensbidrag (refereegranskat)abstract
- The recent progress in our work to implement salt (NaCl) as a dosemeter is presented. Laboratory investigations have indicated a linear dose response from 1 mGy to about 100 mGy and detection limits down to 0.1 mGy. Investigations in the clinic comparing TL-dosimetry in LiF and OSL in NaCl have indicated a similar dose response for the two dosemeters at different photon energies. Field studies with stationary dosemeter kits containing TLDs (LiF) and NaCl suggests that salt is also a good candidate for environmental monitoring of radiation.
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