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Start Over Author "Wiehl, Norbert" Journal radiochimica acta
9 results on '"Wiehl, Norbert"'

1. Online chemical adsorption studies of Hg, Tl, and Pb on SiO2 and Au surfaces in preparation for chemical investigations on Cn, Nh, and Fl at TASCA

Author

Lens, Lotte, primary, Yakushev, Alexander, additional, Düllmann, Christoph Emanuel, additional, Asai, Masato, additional, Ballof, Jochen, additional, Block, Michael, additional, David, Helena May, additional, Despotopulos, John, additional, Di Nitto, Antonio, additional, Eberhardt, Klaus, additional, Even, Julia, additional, Götz, Michael, additional, Götz, Stefan, additional, Haba, Hiromitsu, additional, Harkness-Brennan, Laura, additional, Heßberger, Fritz Peter, additional, Herzberg, Rodi D., additional, Hoffmann, Jan, additional, Hübner, Annett, additional, Jäger, Egon, additional, Judson, Daniel, additional, Khuyagbaatar, Jadambaa, additional, Kindler, Birgit, additional, Komori, Yukiko, additional, Konki, Joonas, additional, Kratz, Jens Volker, additional, Krier, Jörg, additional, Kurz, Nikolaus, additional, Laatiaoui, Mustapha, additional, Lahiri, Susanta, additional, Lommel, Bettina, additional, Maiti, Moumita, additional, Mistry, Andrew K., additional, Mokry, Christoph, additional, Moody, Ken, additional, Nagame, Yuichiro, additional, Omtvedt, Jon Petter, additional, Papadakis, Philippos, additional, Pershina, Valeria, additional, Runke, Jörg, additional, Schädel, Matthias, additional, Scharrer, Paul, additional, Sato, Tetsuya, additional, Shaughnessy, Dawn, additional, Schausten, Brigitta, additional, Thörle-Pospiech, Petra, additional, Trautmann, Norbert, additional, Tsukada, Kazuaki, additional, Uusitalo, Juha, additional, Ward, Andrew, additional, Wegrzecki, Maciej, additional, Wiehl, Norbert, additional, and Yakusheva, Vera, additional

Published
2018
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4. In-situ formation, thermal decomposition, and adsorption studies of transition metal carbonyl complexes with short-lived radioisotopes

Author

Even, Julia, primary, Yakushev, Alexander, additional, Düllmann, Christoph Emanuel, additional, Dvorak, Jan, additional, Eichler, Robert, additional, Gothe, Oliver, additional, Hartmann, Willy, additional, Hild, Daniel, additional, Jäger, Egon, additional, Khuyagbaatar, Jadambaa, additional, Kindler, Birgit, additional, Kratz, Jens Volker, additional, Krier, Jörg, additional, Lommel, Bettina, additional, Niewisch, Lorenz, additional, Nitsche, Heino, additional, Pysmenetska, Inna, additional, Schädel, Matthias, additional, Schausten, Brigitta, additional, Türler, Andreas, additional, Wiehl, Norbert, additional, and Wittwer, David, additional

Published
2014
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6. Online chemical adsorption studies of Hg, Tl, and Pb on SiO2and Au surfaces in preparation for chemical investigations on Cn, Nh, and Fl at TASCA

Author

Lens, Lotte, Yakushev, Alexander, Düllmann, Christoph Emanuel, Asai, Masato, Ballof, Jochen, Block, Michael, David, Helena May, Despotopulos, John, Di Nitto, Antonio, Eberhardt, Klaus, Even, Julia, Götz, Michael, Götz, Stefan, Haba, Hiromitsu, Harkness-Brennan, Laura, Heßberger, Fritz Peter, Herzberg, Rodi D., Hoffmann, Jan, Hübner, Annett, Jäger, Egon, Judson, Daniel, Khuyagbaatar, Jadambaa, Kindler, Birgit, Komori, Yukiko, Konki, Joonas, Kratz, Jens Volker, Krier, Jörg, Kurz, Nikolaus, Laatiaoui, Mustapha, Lahiri, Susanta, Lommel, Bettina, Maiti, Moumita, Mistry, Andrew K., Mokry, Christoph, Moody, Ken, Nagame, Yuichiro, Omtvedt, Jon Petter, Papadakis, Philippos, Pershina, Valeria, Runke, Jörg, Schädel, Matthias, Scharrer, Paul, Sato, Tetsuya, Shaughnessy, Dawn, Schausten, Brigitta, Thörle-Pospiech, Petra, Trautmann, Norbert, Tsukada, Kazuaki, Uusitalo, Juha, Ward, Andrew, Wegrzecki, Maciej, Wiehl, Norbert, and Yakusheva, Vera

Abstract

Online gas-solid adsorption studies with single-atom quantities of Hg, Tl, and Pb, the lighter homologs of the superheavy elements (SHE) copernicium (Cn, Z=112), nihonium (Nh, Z=113), and flerovium (Fl, Z=114), were carried out using short-lived radioisotopes. The interaction with Au and SiO2surfaces was studied and the overall chemical yield was determined. Suitable radioisotopes were produced in fusion-evaporation reactions, isolated in the gas-filled recoil separator TASCA, and flushed rapidly to an adjacent setup of two gas chromatography detector arrays covered with SiO2(first array) and Au (second array). While Tl and Pb adsorbed on the SiO2surface, Hg interacts only weakly and reached the Au-covered array. Our results contribute to elucidating the influence of relativistic effects on chemical properties of the heaviest elements by providing experimental data on these lighter homologs.

Published
2018
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7. Digital liquid-scintillation counting and effective pulse-shape discrimination with artificial neural networks.

Author

Langrock, Gert, Wiehl, Norbert, Kling, Hans-Otto, Mendel, Matthias, Nähler, Andrea, Tharun, Udo, Eberhardt, Klaus, Trautmann, Norbert, Kratz, Jens Volker, Omtvedt, Jon-Petter, and Skarnemark, Gunnar

Subjects
LIQUID scintillation counting, ARTIFICIAL neural networks, LIQUID-liquid extraction, ANALOG electronic systems, SOLVENT extraction, SPECTROMETRY
Abstract

A typical problem in low-level liquid scintillation (LS) counting is the identification of α particles in the presence of a high background of β and γ particles. Especially the occurrence of β- β and β- γ pile-ups may prevent the unambiguous identification of an α signal by commonly used analog electronics. In this case, pulse-shape discrimination (PSD) and pile-up rejection (PUR) units show an insufficient performance. This problem was also observed in own earlier experiments on the chemical behaviour of transactinide elements using the liquid-liquid extraction system SISAK in combination with LS counting. α-particle signals from the decay of the transactinides could not be unambiguously assigned. However, the availability of instruments for the digital recording of LS pulses changes the situation and provides possibilities for new approaches in the treatment of LS pulse shapes. In a SISAK experiment performed at PSI, Villigen, a fast transient recorder, a PC card with oscilloscope characteristics and a sampling rate of 1 giga samples s−1 (1 ns per point), was used for the first time to record LS signals. It turned out, that the recorded signals were predominantly α, β- β and β- γ pile up, and fission events. This paper describes the subsequent development and use of artificial neural networks (ANN) based on the method of 'back-propagation of errors' to automatically distinguish between different pulse shapes. Such networks can 'learn' pulse shapes and classify hitherto unknown pulses correctly after a learning period. The results show that ANN in combination with fast digital recording of pulse shapes can be a powerful tool in LS spectrometry even at high background count rates. [ABSTRACT FROM AUTHOR]

Published
2015
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8. In-situformation, thermal decomposition, and adsorption studies of transition metal carbonyl complexes with short-lived radioisotopes

Author

Even, Julia, Yakushev, Alexander, Düllmann, Christoph Emanuel, Dvorak, Jan, Eichler, Robert, Gothe, Oliver, Hartmann, Willy, Hild, Daniel, Jäger, Egon, Khuyagbaatar, Jadambaa, Kindler, Birgit, Kratz, Jens Volker, Krier, Jörg, Lommel, Bettina, Niewisch, Lorenz, Nitsche, Heino, Pysmenetska, Inna, Schädel, Matthias, Schausten, Brigitta, Türler, Andreas, Wiehl, Norbert, and Wittwer, David

Abstract

AbstractWe report on the in-situsynthesis of metal carbonyl complexes with short-lived isotopes of transition metals. Complexes of molybdenum, technetium, ruthenium and rhodium were synthesized by thermalisation of products of neutron-induced fission of 249Cf in a carbon monoxide-nitrogen mixture. Complexes of tungsten, rhenium, osmium, and iridium were synthesized by thermalizing short-lived isotopes produced in 24Mg-induced fusion evaporation reactions in a carbon monoxide containing atmosphere. The chemical reactions took place at ambient temperature and pressure conditions. The complexes were rapidly transported in a gas stream to collection setups or gas phase chromatography devices. The physisorption of the complexes on Au and SiO2surfaces was studied. We also studied the stability of some of the complexes, showing that these start to decompose at temperatures above 300 ℃ in contact with a quartz surface. Our studies lay a basis for the investigation of such complexes with transactinides.

Published
2014
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9. TASCAを用いたCn, Nh, Fl化学実験のためのHg, Tl, PbのSiO2及びAu表面に対するオンライン化学吸着研究

Author

Lotte Lens, Alexander Yakushev, Christoph Emanuel Düllmann, Masato Asai, Jochen Ballof, Michael Block, Helena May David, John Despotopulos, Antonio Di Nitto, Klaus Eberhardt, Julia Even, Michael Götz, Stefan Götz, Hiromitsu Haba, Laura Harkness-Brennan, Fritz Peter Heßberger, Rodi D. Herzberg, Jan Hoffmann, Annett Hübner, Egon Jäger, Daniel Judson, Jadambaa Khuyagbaatar, Birgit Kindler, Yukiko Komori, Joonas Konki, Jens Volker Kratz, Jörg Krier, Nikolaus Kurz, Mustapha Laatiaoui, Susanta Lahiri, Bettina Lommel, Moumita Maiti, Andrew K. Mistry, Christoph Mokry, Ken Moody, Yuichiro Nagame, Jon Petter Omtvedt, Philippos Papadakis, Valeria Pershina, Jörg Runke, Matthias Schädel, Paul Scharrer, Tetsuya Sato, Dawn Shaughnessy, Brigitta Schausten, Petra Thörle-Pospiech, Norbert Trautmann, Kazuaki Tsukada, Juha Uusitalo, Andrew Ward, Maciej Wegrzecki, Norbert Wiehl, Vera Yakusheva, Research unit Nuclear & Hadron Physics, Lens, Lotte, Yakushev, Alexander, Düllmann, Christoph Emanuel, Asai, Masato, Ballof, Jochen, Block, Michael, David, Helena May, Despotopulos, John, Di Nitto, Antonio, Eberhardt, Klau, Even, Julia, Götz, Michael, Götz, Stefan, Haba, Hiromitsu, Harkness-Brennan, Laura, Heßberger, Fritz Peter, Herzberg, Rodi D., Hoffmann, Jan, Hübner, Annett, Jäger, Egon, Judson, Daniel, Khuyagbaatar, Jadambaa, Kindler, Birgit, Komori, Yukiko, Konki, Joona, Kratz, Jens Volker, Krier, Jörg, Kurz, Nikolau, Laatiaoui, Mustapha, Lahiri, Susanta, Lommel, Bettina, Maiti, Moumita, Mistry, Andrew K., Mokry, Christoph, Moody, Ken, Nagame, Yuichiro, Omtvedt, Jon Petter, Papadakis, Philippo, Pershina, Valeria, Runke, Jörg, Schädel, Matthia, Scharrer, Paul, Sato, Tetsuya, Shaughnessy, Dawn, Schausten, Brigitta, Thörle-Pospiech, Petra, Trautmann, Norbert, Tsukada, Kazuaki, Uusitalo, Juha, Ward, Andrew, Wegrzecki, Maciej, Wiehl, Norbert, and Yakusheva, Vera

Subjects
Analytical chemistry, chemistry.chemical_element, Electronic structure, 010402 general chemistry, 01 natural sciences, adsorption studie, thermochromatography, Homologs of superheavy element, RELATIVISTIC PERIODIC DFT, Metal, GSI, Adsorption, CHEMISTRY, 0103 physical sciences, isothermal chromatography, Physical and Theoretical Chemistry, SUPERHEAVY ELEMENTS, 010306 general physics, Copernicium, Chemistry, QUARTZ SURFACE, 0104 chemical sciences, gas phase chromatography of single atom, HEAVIEST ELEMENTS, Flerovium, ELECTRONIC-STRUCTURE, visual_art, Yield (chemistry), METAL, visual_art.visual_art_medium, Gas chromatography, Relativistic quantum chemistry, physical preseparation, SYSTEM
Abstract

Online gas-solid adsorption studies with single atom quantities of Hg, Tl, and Pb on SiO$_{2}$ and Au surfaces were carried out using short-lived radioisotopes with half-lives in the range of 4-49 s. This is a model study to measure adsorption enthalpies of superheavy elements Cn, Nh, and Fl. The short-lived isotopes were produced and separated by the gas-filled recoil separator TASCA at GSI. The products were stopped in He gas, and flushed into gas chromatography columns made of Si detectors whose surfaces were covered by SiO$_{2}$ or Au. The short-lived Tl and Pb were successfully measured by the Si detectors with the SiO$_{2}$ surface at room temperature. On the other hand, the Hg did not adsorb on the SiO$_{2}$ surface, but adsorbed on the Au surface. The results demonstrated that the adsorption properties of short-lived Hg, Tl, and Pb could be studied with this setup, and that this method is applicable to the experiment for Cn, Nh, and Fl., 半減期4$\sim$49秒の短寿命同位体を用いて、水銀(Hg), タリウム(Tl), 鉛(Pb)の単一原子レベルでのSiO$_{2}$及びAu表面への固体吸着挙動をオンライン気相実験により調べた。超重元素Cn, Nh, Flの吸着エンタルピー測定のためのモデル実験として実施した。短寿命同位体はドイツ重イオン研究所の反跳核分離装置TASCAを用いて生成・分離した。生成核はヘリウムガス中に捕集された後、SiO$_{2}$あるいはAuで表面を覆われたSi検出器で作製されたガスクロマトグラフィーカラムへと導入した。短寿命Tl及びPb同位体は室温においてSiO$_{2}$表面に吸着し、Si検出器で測定することに成功した。一方、HgはSiO$_{2}$表面には吸着せず、Au表面に吸着した。この結果より、本実験のセットアップを用いることで短寿命Hg, Tl, Pb同位体の吸着特性を調べることができると証明され、この手法がCn, Nh, Flの実験にも適用できることが確認された。

Published
2018

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