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Seibersdorf, Austria

Loiseau P.,Dosimetry Laboratory | Geslot B.,CEA Cadarache Center | Andre J.,Aix - Marseille University
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2013

Fission Chambers (FCs) are widely used as neutron detectors for online flux measurement. The FC current pulse charge is a key observable quantity which depends on specifications such as the filling gas pressure and the FC geometry. In order to study pulse charges, experimental data have been acquired at the Cadarache zero power reactor MINERVE. Two chambers with contrasting specifications have been used. The experimental pulse charge spectrum is interpreted by the mean of a modeling of fission products (FPs) energy deposition within the filling gas. The pulse charge spectrum peaks are found to correspond to FP emitted perpendicularly to the electrodes. © 2013 Published by Elsevier B.V. Source


Chatgilialoglu C.,National Research Council Italy | Ferreri C.,National Research Council Italy | Lykakis I.N.,Aristotle University of Thessaloniki | Mihaljevic B.,Dosimetry Laboratory
Israel Journal of Chemistry | Year: 2014

Different types of lipid aggregations, such as micelles and liposomes, can be used as biomimetic models. The uses of γ-irradiation as a valid methodology for simulating the biological generation of thiyl radicals in these models are summarized and, in particular, thiyl radical catalyzed cis-trans isomerization of unsaturated lipids is underlined. The efficiency of antioxidants against lipid isomerization assayed by biomimetic models and the importance of trans lipids as novel biomarkers of radical stress are also described. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Pressyanov D.S.,Dosimetry Laboratory
Nukleonika | Year: 2010

An overview of ongoing directions of radon studies in the Faculty of Physics, St. Kliment Ohridski University of Sofia is presented. The focus is on: 1) Study and implementation of the polycarbonate method for measuring 222Rn. In this respect the results from laboratory and field experience with this method are summarized. Its potential for precise retrospective measurements by home stored CDs/DVDs is emphasized. 2) Surveys in radon risk areas in the country. The approaches and results in this direction are illustrated on the example of the town of Rakovski. In this town lung cancer risk is twice increased for both sexes. Significantly high 222Rn concentrations were observed in most of the houses and this can be the major factor contributing to the risk. 3) Mitigation of dwellings with high radon content. Mitigation works were recently initiated and our experience with passive radon barriers and active sub-slab depressurization systems is shared. Summarizing the results in all the three directions we conclude that there is a basis to enhance radon research and practice in the country. To be more efficient, these activities need collaboration with medical authorities, civil engineers and, especially in research, with international teams working in the field. Source


Mitev K.K.,Dosimetry Laboratory
Applied Radiation and Isotopes | Year: 2016

This work demonstrates that common plastic scintillators like BC-400, EJ-200 and SCSF-81 absorb radon and their scintillation pulse decay times are different for alpha- and beta-particles. This allows the application of pulse shape analysis for separation of the pulses of alpha- and beta-particles emitted by the absorbed radon and its progeny. It is shown that after pulse shape discrimination of beta-particles' pulses, the energy resolution of BC-400 and EJ-200 alpha spectra is sufficient to separate the peaks of 222Rn, 218Po and 214Po and allows 222Rn measurements that are unaffected by the presence of thoron (220Rn) in the environment. The alpha energy resolution of SCSF-81 in the experiments degrades due to imperfect collection of the light emitted inside the scintillating fibers. The experiments with plastic scintillation microspheres (PSM) confirm previous findings of other researchers that PSM have alpha-/beta-discrimination properties and show suitability for radon measurements. The diffusion length of radon in BC-400 and EJ-200 is determined. The pilot experiments show that the plastic scintillators are suitable for radon-in-soil-gas measurements. Overall, the results of this work suggest that it is possible to develop a new type of radon measurement instruments which employ absorption in plastic scintillators, pulse-shape discrimination and analysis of the alpha spectra. Such instruments can be very compact and can perform continuous, real-time radon measurements and thoron detection. They can find applications in various fields from radiation protection to earth sciences. © 2016 Elsevier Ltd. Source


Filliatre P.,Dosimetry Laboratory | Jammes C.,Dosimetry Laboratory | Jeannot J.-P.,CEA Cadarache Center | Jadot F.,CEA Cadarache Center
Annals of Nuclear Energy | Year: 2014

With appropriate techniques, the information brought by the in-vessel instrumentation of nuclear reactors may betray rather subtle departures from normal state indicating an abnormal situation at early stages, to improve both safety and availability. This paper takes the case of the detection of delayed neutrons released by a clad failure in sodium-cooled fast neutron reactors as an illustrative application of hypothesis testing. Two methods are discussed, seeking either for a counting excess of for a departure from stationarity, yielding similar results. The question of false alarms is addressed by a Bayesian approach that takes into account the prior probability of failure. The use of several identical sensors is shown to be effective. © 2013 Elsevier Ltd. All rights reserved. Source

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