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S tudent P ractice in JINR Fields of Research Dubna 13.7.-31.7.2011. Vlasta Zdychová , Martina Benešová CTU in Prague Czech Republic Pavol Blahušiak , Alexander Szabó , Juraj Sabo UK in Bratislava Slovakia Supervisor: prof. M. V. Frontasyeva. Neutron Activation Analysis.
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StudentPracticein JINR FieldsofResearchDubna 13.7.-31.7.2011 Vlasta Zdychová, Martina Benešová CTU in PragueCzechRepublic Pavol Blahušiak, Alexander Szabó, Juraj Sabo UK in Bratislava Slovakia Supervisor: prof. M. V. Frontasyeva
Neutron Activation Analysis Department of NAA and Applied Research Division of Nuclear Physics Frank Laboratory of Neutron Physics Joint Institute for Nuclear Research Dubna
Introduction • NAA wasdiscovered in 1936 by G. Hevesy (Hungary) and H. Levi (Denmark), whofoundthesamplescontaining REE. • Neutron activation analysis is an isotopespecificanalytical technique for the qualitativeand quantitative determination ofelemental content.
Energy distribution of neutron flux Thermal 0.025 eV-0.5 eV Epithermal 0.5 eV-100 keV Fast 100 keV-25 MeV
Types of NAA • Destructive (radiochemical) – the resulting radioactive sample is chemically decomposed and the elements are chemically separated. • Non-destructive (instrumental) – sample is kept intact and the radionuclides are determined, taking advantage of the differences in decay rates via measurements at different decay intervals.
Characteristics of INAA • Non-destructive analysis • Multi-element analytical technique • The chemical formand physical state of theelements donot influence the activation anddecayprocess • Suitable even for determination of masses in the order of 10–6–10–9 g and less
IBR-2 Pulsed Reactor at FLNP in JINR • averageheatpower 2 MW • peakpulsepower 1500 MW • averagethermalneutronflux 1013 cm-2s-1 • 3-loop coolingsystemensuresappropriateconditionsforbiologicalsamples (60-70°C)
Project Regata - Biomonitoringof atmosphericdepositionof heavy metals and otherelements • Moss collection • Preparation of samples for irradiation • Pellets irradiation • Detection of activated elements • Analysis
Analysis of spectra • peakrecognition • peakfitting • assignmentofspecific • peaks to radionuclides • determinationof • activity • frompeakarea
Conclusion • Theory of NAA • Preparing of samples for irradiation • Calibration and adjustment of semiconductor detectors • Analysis of gamma spectra • Determination activity and concentrations of interested elements
References • P. Bode, J. J. M. de Goeij, ActivationAnalysis, Encyclopedia of Environmental Analysis and Remediation • P. Bode, Instrumental and organizational aspects of a neutron activation analysis laboratory • M. V. Frontasyeva, NeutronActivationAnalysis in theLifeSciences • http://archaeometry.missouri.edu/naa_overview.html • http://flnp.jinr.ru/34/