| 1. |
- Rondahl, Stina Holmgren, et al.
(författare)
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Comparing results of X-ray diffraction, µ-Raman spectroscopy and neutron diffraction when identifying chemical phases in seized nuclear material, during a comparative nuclear forensics exercise
- 2018
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Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer Science and Business Media LLC. - 0236-5731 .- 1588-2780. ; 315:2, s. 395-408
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Tidskriftsartikel (refereegranskat)abstract
- This work presents the results for identification of chemical phases obtained by several laboratories as a part of an international nuclear forensic round-robin exercise. In this work powder X-ray diffraction (p-XRD) is regarded as the reference technique. Neutron diffraction produced a superior high-angle diffraction pattern relative to p-XRD. Requiring only small amounts of sample, µ-Raman spectroscopy was used for the first time in this context as a potentially complementary technique to p-XRD. The chemical phases were identified as pure UO 2 in two materials, and as a mixture of UO 2 , U 3 O 8 and an intermediate species U 3 O 7 in the third material.
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| 2. |
- Rondahl, Stina Holmgren, et al.
(författare)
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Evaluation of different methods for measuring 89Sr and 90Sr: Measurement uncertainty for the different methods as a function of the activity ratio
- 2018
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Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043 .- 1872-9800. ; 140, s. 87-95
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Tidskriftsartikel (refereegranskat)abstract
- In case of a radiological emergency situation involving e.g. fission of uranium or plutonium, analysis of radioactive strontium will be of importance. The primary radionuclides of interest are90Sr, its progeny90Y and89Sr. A few days following an event,89Sr will be the predominant radioisotope of strontium. Most methods found in the literature are valid and applicable when measuring90Sr, but when samples contain both89Sr/90Sr interference problematics arise. How these interferences are dealt with will have an effect on the uncertainty of the90Sr determination. This work aims at evaluating three measurement approaches, all mentioned in the literature, with respect to the measurement uncertainty when determining90Sr in an emergency preparedness situation and to propose a suitable measurement strategy.
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| 3. |
- Rondahl, Stina Holmgren, et al.
(författare)
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Time optimization of 90Sr determinations: sequential measurement of multiple samples during decay of 90Y
- 2017
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Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer Science and Business Media LLC. - 0236-5731 .- 1588-2780. ; 311:2, s. 1143-1148
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Tidskriftsartikel (refereegranskat)abstract
- This work presents an optimized method for the determination of multiple samples containing 90Sr when its daughter 90Y is measured after chemical separation and in sequence, i.e. during its decay. Consequently the measurement times will increase for each subsequent sample, since there has been a longer time for decay before measurement. Compared to a previously published approach, when 90Y is measured during its ingrowth, the gain in total analysis time (time for ingrowth+ summation of measurement times) is not that large, particularly not for low background instruments. However, results for a large part of the samples can be delivered earlier.
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