18 research outputs found
Ăšj adatkönyvtár kĂ©szĂtĂ©se hideg neutronos prompt gamma aktiváciĂłs analĂzishez = New data library for prompt gamma activation analysis with cold neutrons
A kutatás cĂ©lja a prompt gamma aktiváciĂłs analĂzis korábban kifejlesztett adatkönyvtárának pontosĂtása volt. Ehhez felĂşjĂtottuk a mintaelĹ‘kĂ©szĂtĹ‘ laboratĂłriumunkat, nagy tisztaságĂş Ăşj vegyszereket vásároltuk (egy másik pályázat keretĂ©ben) felĂşjĂtottuk a mĂ©rĹ‘rendszerĂĽnket. Az Ăşj berendezĂ©sen nagyobb neutron-fluxus mellett nagyobb hatásfokkal, ugyanakkor kisebb mintatömegeket alkalmazva ĂşjramĂ©rtĂĽk az egyes elemek parciális gammakeltĂ©si hatáskeresztmetszeteit Ă©s meghatároztuk a karakterisztikus vonalak energiáit. A legfontosabb (elsĹ‘sorban a könnyű elemek) esetĂ©ben nagy felbontásĂş detektorral is vĂ©geztĂĽnk mĂ©rĂ©seket a korábban feloldhatatlan spektrális átfedĂ©sek felbontása cĂ©ljábĂłl. E mĂ©rĂ©sekkel párhuzamosan bomlási gamma-csĂşcsok hatáskeresztmetszetĂ©t is meghatároztuk. A spektrumokat kiĂ©rtĂ©keltĂĽk. Az Ăşj adatokat folyamatosan visszĂĽk be az adatbázisokba. Az adatkönyvtár revĂziĂłját számos mĂłdszertani fejlesztĂ©sĂĽnk is segĂti. Ăšj kalibrálĂł standard adatokat határoztunk meg, kidolgoztuk a hibaszámĂtás mĂłdszereit a standardizáláshoz Ă©s az összetĂ©tel meghatározásához, továbbfejlesztettĂĽk az összetĂ©tel számĂtĂł programot. Mindezek egyre pontosabb Ă©s megbĂzhatĂłbb kĂ©miai analĂzist tesznek lehetĹ‘vĂ© ezzel is segĂtve a berendezĂ©sĂĽnknĂ©l folyĂł kutatĂłmunkát. | The objectives of this project were to improve the earlier version of the spectroscopic data library used in prompt gamma activation analysis. For this purpose our sample preparation laboratory was renovated, a collection of new chemical compounds was purchased and the PGAA system was also upgraded. The increased neutron flux and the higher counting efficiency made possible measurements of higher accuracy. Smaller sample masses could be used, which made several corrections unnecessary, further improving the reliability of our results. Spectroscopic data for the important characteristic lines were determined. A high-resolution germanium detector was also used to resolve multiplets, which proved to be too complicated when acquired with the standard germanium detector of the PGAA facility. A series of short-lived nuclides were also measured, and their cross-sections were accurately determined. The spectra have been evaluated. The results are being uploaded in the spectroscopic database. Our methodological developments help the revision of the data library: new calibration data were determined to improve the method of the efficiency calculation, a new method for the determination of the uncertainties was also developed. The software used for the determination of the chemical composition was also developed. These efforts make the chemical analyses and the research, performed at our facility, more reliable
Benchmarking PGAA, in-beam NAA, reactor-NAA and handheld XRF spectrometry for the element analysis of archeological bronzes
Novel detection strategies were developed to improve the PGAA methodology in the analysis of bronze and brass objects. Instrumental neutron activation analysis and X-ray fluorescence were also involved in this study for comparison. The approach was tested on a set of IRMM-certified copper alloys. Reference values for the concentrations of four major additive components (As, Zn, Sn, and Pb) were compared with the results obtained by the involved methods. The bias observed between the reference Sn values and the initial PGAA results was successfully addressed by considering the interference of this line with low intensity copper prompt gamma peaks. In this report results are presented, and the analytical merits are compared
Precise measurement of the thermal and stellar Fe 54 (n,Îł) Fe 55 cross sections via accelerator mass spectrometry
Roncsolásmentes képalkotás neutronokkal és röntgensugárzással a Budapesti Neutron Centrumban
A neutronos Ă©s röntgenkĂ©palkotással mĂ©lysĂ©gi, akár idĹ‘felbontott szerkezeti informáciĂłt kaphatunk kĂ©t Ă©s három dimenziĂłban megjelenĂtve, roncsolásmentesen. A Budapesti Neutron Centrumban a közelmĂşltban vĂ©gzett technikai fejlesztĂ©seknek köszönhetĹ‘en nemzetközileg is jegyzett mĂ©rĹ‘helyek állnak rendelkezĂ©sĂĽnkre, amely a felhasználĂłi programok, illetve kĂ©toldalĂş megállapodások rĂ©vĂ©n hozzáfĂ©rhetĹ‘k a magyar Ă©s a nemzetközi kutatĂłi közössĂ©g (CERIC-ERIC, IPERION CH), valamint az ipar számára (SINE 2020)
Innováció és a 60 éves Budapesti Kutatóreaktor
Az MTA csillebérci kampuszán lévõ Budapesti Kutatóreaktor
idén ünnepelte 60 éves fennállását – elõször
1959. március 25-én kezdte meg mûködését. Ez
egy kiemelkedõ jelentõségû mérföldkõ volt a magyar
tudomány és technológia fejlõdésében: a Budapesti
Kutatóreaktor (BKR) folyamatosan megújuló és bõvülõ
mûszerparkja azóta is a legnagyobb, jelentõs
számú felhasználót kiszolgáló kutatási infrastruktúra
hazánkban, sõt a közép-európai régióban is. A BKR
megbĂzhatĂł ĂĽzemelĂ©sĂ©vel meghatározĂł szerepet játszik
az európai neutronkutatási közösség életében is,
és az elkövetkezõ évtizedben ez még hangsúlyosabb
lesz, hiszen egyre több európai ország dönt úgy,
hogy hasonlĂł tĂpusĂş kutatĂłreaktorait bezárja. Jelenleg
mintegy 200 hazai és – két éves átlagban – körülbelül
ugyanannyi külföldi kutató használja a neutronos
módszereket, munkájukhoz a jövõben is a BKR
által biztosĂtott neutronok szolgáltatják a kĂsĂ©rleti
hátteret, amihez a reaktor Ă©lettartamának hosszabbĂtását
tervezik
5,000 years old Egyptian iron beads made from hammered meteoritic iron
The earliest known iron artefacts are nine small beads securely dated to circa 3200 BC, from two burials in Gerzeh, northern Egypt. We show that these beads were made from meteoritic iron, and shaped by careful hammering the metal into thin sheets before rolling them into tubes. The study demonstrates the ability of neutron and X-ray methods to determine the nature of the material even after complete corrosion of the iron metal. The iron beads were strung into a necklace together with other exotic minerals such as lapis lazuli, gold and carnelian, revealing the status of meteoritic iron as a special material on a par with precious metal and gem stones. The results confirm that already in the fourth millennium BC metalworkers had mastered the smithing of meteoritic iron, an iron–nickel alloy much harder and more brittle than the more commonly worked copper. This is of wider significance as it demonstrates that metalworkers had already nearly two millennia of experience to hot-work meteoritic iron when iron smelting was introduced. This knowledge was essential for the development of iron smelting, which produced metal in a solid state process and hence depended on this ability in order to replace copper and bronze as the main utilitarian metals
High-resolution study of the 113
The gamma-ray spectrum and the decay scheme of 114Cd obtained from a radiative neutron capture experiment on 113Cd samples are modelled in the framework of extreme statistical model. The unfolding of the experimental spectrum with proper normalization yields a total capture cross section of 21640 b and an average gamma-ray multiplicity of 4.1. Using the extreme statistical model the development of the low energy decay scheme of 114Cd is in progress. In the model the constant-temperature level density is used, where the temperature parameter was very sensitive to the shape of the modelled gamma-ray spectrum. Using this sensitivity T = 0.62 MeV was obtained with the constraint of good description of low energy level density and the level density at the binding energy. This is in full agreement with our earlier publication. For the description of the continuum shape of the unfolded spectrum the inclusion of low energy enhancement for the photon strength function was an important new addition