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35 results on '"Mokry, Christoph"'

1. Smooth trends in fermium charge radii and the impact of shell effects

Author

Warbinek, Jessica, Rickert, Elisabeth, Raeder, Sebastian, Albrecht-Schönzart, Thomas, Andelic, Brankica, Auler, Julian, Bally, Benjamin, Bender, Michael, Berndt, Sebastian, Block, Michael, Brizard, Alexandre, Chauveau, Pierre, Cheal, Bradley, Chhetri, Premaditya, Claessens, Arno, de Roubin, Antoine, Devlin, Charlie, Dorrer, Holger, Düllmann, Christoph E., Ezold, Julie, Ferrer, Rafael, Gadelshin, Vadim, Gaiser, Alyssa, Giacoppo, Francesca, Goriely, Stephane, Gutiérrez, Manuel J., Harvey, Ashley, Hasse, Raphael, Heinke, Reinhard, Heßberger, Fritz-Peter, Hilaire, Stephane, Kaja, Magdalena, Kaleja, Oliver, Kieck, Tom, Kim, EunKang, Kneip, Nina, Köster, Ulli, Kraemer, Sandro, Laatiaoui, Mustapha, Lantis, Jeremy, Lecesne, Nathalie, Loria Basto, Andrea Tzeitel, Mistry, Andrew Kishor, Mokry, Christoph, Moore, Iain, Murböck, Tobias, Münzberg, Danny, Nazarewicz, Witold, Niemeyer, Thorben, Nothhelfer, Steven, Péru, Sophie, Raggio, Andrea, Reinhard, Paul-Gerhard, Renisch, Dennis, Rey-Herme, Emmanuel, Romans, Jekabs, Romero Romero, Elisa, Runke, Jörg, Ryssens, Wouter, Savajols, Hervé, Schneider, Fabian, Sperling, Joseph, Stemmler, Matou, Studer, Dominik, Thörle-Pospiech, Petra, Trautmann, Norbert, Urquiza-González, Mitzi, van Beek, Kenneth, Van Cleve, Shelley, Van Duppen, Piet, Vandebrouck, Marine, Verstraelen, Elise, Walther, Thomas, Weber, Felix, and Wendt, Klaus

Published
2024
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2. Measurement of the $^{229}$Th isomer energy with a magnetic micro-calorimeter

Author

Sikorsky, Tomas, Geist, Jeschua, Hengstler, Daniel, Kempf, Sebastian, Gastaldo, Loredana, Enss, Christian, Mokry, Christoph, Runke, Jörg, Düllmann, Christoph E., Wobrauschek, Peter, Beeks, Kjeld, Rosecker, Veronika, Sterba, Johannes H., Kazakov, Georgy, Schumm, Thorsten, and Fleischmann, Andreas

Subjects
Nuclear Experiment, Nuclear Theory, Physics - Instrumentation and Detectors
Abstract

We present a measurement of the low-energy (0--60$\,$keV) $\gamma$ ray spectrum produced in the $\alpha$-decay of $^{233}$U using a dedicated cryogenic magnetic micro-calorimeter. The energy resolution of $\sim$$10\,$eV, together with exceptional gain linearity, allow us to measure the energy of the low-lying isomeric state in $^{229}$Th using four complementary evaluation schemes. The most accurate scheme determines the $^{229}$Th isomer energy to be $8.10(17)\,$eV, corresponding to 153.1(37)$\,$nm, superseding in precision previous values based on $\gamma$ spectroscopy, and agreeing with a recent measurement based on internal conversion electrons. We also measure branching ratios of the relevant excited states to be $b_{29}=9.3(6)\%$ and $b_{42}=0.3(3)\%$., Comment: 5 pages, 5 figures + supplementary

Published
2020
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3. Alpha spectrometric characterization of thin $^{233}$U sources for $^{229\text{(m)}}$Th production

Author

Haas, Raphael, Hufnagel, Michelle, Abrosimov, Roman, Düllmann, Christoph E., Krupp, Dominik, Mokry, Christoph, Renisch, Dennis, Runke, Jörg, and Scherer, Ulrich W.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

Four different techniques were applied for the production of $^{233}$U alpha recoil ion sources, providing $^{229}$Th ions. They were compared with respect to a minimum energy spread of the $^{229}$Th recoil ions, using the emitted alpha particles as an indicator. The techniques of Molecular Plating, Drop-on-Demand inkjet printing, chelation from dilute nitric acid solution on chemically functionalized silicon surfaces, and self-adsorption on passivated titanium surfaces were used. All fabricated sources were characterized by using alpha spectrometry, radiographic imaging, and scanning electron microscopy. A direct validation for the estimated recoil ion rate was obtained by collecting $^{228}$Th recoil ions from $^{232}$U recoil ion sources prepared by self-adsorption and Molecular Plating. The chelation and the self-adsorption based approaches appear most promising for the preparation of recoil ion sources delivering monochromatic recoil ions., Comment: 20 pages, 14 figures, 11 tables, ahead of print at Radiochim. Acta (2020)

Published
2020
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4. Direct detection of the 229Th nuclear clock transition

Author

von der Wense, Lars, Seiferle, Benedict, Laatiaoui, Mustapha, Neumayr, Jürgen B., Maier, Hans-Jörg, Wirth, Hans-Friedrich, Mokry, Christoph, Runke, Jörg, Eberhardt, Klaus, Düllmann, Christoph E., Trautmann, Norbert G., and Thirolf, Peter G.

Subjects
Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

Today's most precise time and frequency measurements are performed with optical atomic clocks. However, it has been proposed that they could potentially be outperformed by a nuclear clock, which employs a nuclear transition instead of the atomic shell transitions used so far. By today there is only one nuclear state known which could serve for a nuclear clock using currently available technology, which is the isomeric first excited state in $^{229}$Th. Here we report the direct detection of this nuclear state, which is a further confirmation of the isomer's existence and lays the foundation for precise studies of the isomer's decay parameters. Based on this direct detection the isomeric energy is constrained to lie between 6.3 and 18.3 eV, and the half-life is found to be longer than 60 s for $^{229\mathrm{m}}$Th$^{2+}$. More precise determinations appear in reach and will pave the way for the development of a nuclear frequency standard.

Published
2017
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6. Measurement of the fission yield of 136Cs in the 239Pu(nth,f) reaction

Author

Chebboubi Abdelaziz, Bernard David, Vallet Vanessa, Kessedjian Grégoire, Méplan Olivier, Kim Yung Hee, Köster Ulli, Géhin Florian, Sage Christophe, Ramdhane Mourad, Houdouin-Quenault Maxime, Düllmann Christoph E., Mokry Christoph, Runke Jörg, Renisch Dennis, Litaize Olivier, and Serot Olivier

Subjects
Physics, QC1-999
Abstract

A recent experimental campaign performed at the LOHENGRIN spectrometer at ILL aimed at measuring the independent fission yield of 136Cs in the 239Pu(nth,f) reaction. This nuclide can have an important contribution to the total dose rate coming from spent light water reactor UOX and MOX fuels. Moreover, its impact is of first order on the uncertainty of the total dose rate calculated in specific areas of Nuclear Power Plants within accidental conditions. One of the most important sources of uncertainty is its independent fission yield. Therefore, a new measurement of its independent yield along with a rigorous uncertainty analysis was performed. Due to its low independent yield, a new measurement technique has been applied. Ions recoiling from neutron-irradiated 239Pu target were collected by implantation into an Al foil placed inside a vacuum chamber. This foil was then transferred to a low γ-ray background setup located at nearby laboratory (LPSC). The procedure was then repeated for different LOHENGRIN settings. Compared to the JEFF-3.1.1 library, a decrease of the fission yield of 136Cs with a reduced uncertainty is obtained.

Published
2023
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7. Actinide and lanthanide thin-layer developments using a drop-on-demand printing system

Author

Renisch Dennis, Düllmann Christoph E., Abrosimov Roman, Eberhardt Klaus, Kindler Birgit, Lommel Bettina, Lukacova Jana, Mokry Christoph, Oberstedt Stephan, Pohjalainen Ilkka, Runke Jörg, Schwab Tanyel, and Sirleaf Christopher

Subjects
Physics, QC1-999
Abstract

Actinide and lanthanide thin layers with specific requirements regarding thickness, homogeneity, chemical purity, mechanical stability, and backing properties are applied in a multitude of physics and chemistry experiments. A novel target preparation method, the so-called “Drop-on-Demand” (DoD) technique, based on a commercial nanoliter (nL) dispenser is applied since a few years in the Nuclear Chemistry unit at Johannes Gutenberg University Mainz. The wetting behaviour of the nL droplets on the substrate’s surface is a key parameter determining the spatial distribution of the deposited material after evaporation. By switching from aqueous to organic solvents as well as by substrate surface modifications, the wetting behaviour can be influenced. Recent investigations on this influence and applications of the DoD method are presented. The produced actinide deposits were characterized by optical and scanning electron microscopy, by α spectroscopy as well as by radiographic imaging.

Published
2023
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9. Preparation and characterization of 239Pu and 240Pu recoil ion sources, providing 235mU and 236U for laser-spectroscopic study

Author

Reed, Lauren E., Raggio, Andrea, Renisch, Dennis, Block, Michael, Düllmann, Christoph E., Julin, Jaakko, Kivekäs, Mikko, Laitinen, Mikko, Mokry, Christoph, Moore, Iain D., Pohjalainen, Ilkka, Runke, Jörg, Sajavaara, Timo, Thörle-Pospiech, Petra, and Warbinek, Jessica

Abstract

Oral presentation on preparing and characterising Pu-239 recoil ion sources provided U-235m for laser-spectroscopic study given by L. E. Reed at Actinides Conference 2023, June 5-8, 2023, Colorado School of Mines, Golden, CO, USA.

Published
2023
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10. Preparation and characterization of 239Pu and 240Pu recoil ion sources for 235mU study

Author

Reed, Lauren E., Raggio, Andrea, Renisch, Dennis, Block, Michael, Düllmann, Christoph E., Julin, Jaakko, Kivekäs, Mikko, Laitinen, Mikko, Mokry, Christoph, Moore, Iain D., Pohjalainen, Ilkka, Runke, Jörg, Sajavaara, Timo, Thörle-Pospiech, Petra, and Warbinek, Jessica

Abstract

Oral presentation on preparation and characterization of Pu-239 and Pu-240 recoil ion sources for U-235mstudy given by L.E. Reedat the LISA Conference, May 22-26,2023, Leuven, Belgium.

Published
2023
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11. Nuclear moments and isotope shifts of the actinide isotopes Cf249–253 probed by laser spectroscopy

Author

Weber, Felix, primary, Albrecht-Schönzart, Thomas E., additional, Allehabi, Saleh O., additional, Berndt, Sebastian, additional, Block, Michael, additional, Dorrer, Holger, additional, Düllmann, Christoph E., additional, Dzuba, Vladimir A., additional, Ezold, Julie G., additional, Flambaum, Victor V., additional, Gadelshin, Vadim, additional, Goriely, Stephane, additional, Harvey, Ashley, additional, Heinke, Reinhard, additional, Hilaire, Stephane, additional, Kaja, Magdalena, additional, Kieck, Tom, additional, Kneip, Nina, additional, Köster, Ulli, additional, Lantis, Jeremy, additional, Mokry, Christoph, additional, Münzberg, Danny, additional, Nothhelfer, Steven, additional, Oberstedt, Stephan, additional, Péru, Sophie, additional, Raeder, Sebastian, additional, Runke, Jörg, additional, Sonnenschein, Volker, additional, Stemmler, Matou, additional, Studer, Dominik, additional, Thörle-Pospiech, Petra, additional, Tomita, Hideki, additional, Trautmann, Norbert, additional, Van Cleve, Shelley, additional, Warbinek, Jessica, additional, and Wendt, Klaus, additional

Published
2023
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12. Nuclear moments and isotope shifts of the actinide isotopes Cf 249 – 253 probed by laser spectroscopy

Author

Weber, Felix, Albrecht-Schönzart, Thomas E., Allehabi, Saleh O., Berndt, Sebastian, Block, Michael, Dorrer, Holger, Düllmann, Christoph Emanuel, Dzuba, Vladimir A., Ezold, Julie G., Flambaum, Victor V., Gadelshin, Vadim, Goriely, Stephane, Harvey, Ashley, Heinke, Reinhard, Hilaire, Stephane, Kaja, Magdalena, Kieck, Tom, Kneip, Nina, Köster, Ulli, Lantis, Jeremy, Mokry, Christoph, Münzberg, Danny, Nothhelfer, Steven, Oberstedt, Stephan, Péru, Sophie, Raeder, Sebastian, Runke, Jörg, Sonnenschein, Volker, Stemmler, Matou, Studer, Dominik, Thörle-Pospiech, Petra, Tomita, Hideki, Trautmann, Norbert, Van Cleve, Shelley, Warbinek, Jessica, and Wendt, Klaus

Abstract

Physical review / C 107(3), 034313 (2023). doi:10.1103/PhysRevC.107.034313, Published by Inst., Woodbury, NY

Published
2023
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13. Nuclear moments and isotope shifts of the actinide isotopes Cf249–253 probed by laser spectroscopy

Author

Weber, Felix, Albrecht-Schönzart, Thomas E, Allehabi, Saleh O, Berndt, Sebastian, Block, Michael, Dorrer, Holger, Düllmann, Christoph E, Dzuba, Vladimir A, Ezold, Julie G, Flambaum, Victor V, Gadelshin, Vadim, Goriely, Stephane, Harvey, Ashley, Heinke, Reinhard, Hilaire, Stephane, Kaja, Magdalena, Kieck, Tom, Kneip, Nina, Köster, Ulli, Lantis, Jeremy, Mokry, Christoph, Münzberg, Danny, Nothhelfer, Steven, Oberstedt, Stephan, Péru, Sophie, Raeder, Sebastian, Runke, Jörg, Sonnenschein, Volker, Stemmler, Matou, Studer, Dominik, Thörle-Pospiech, Petra, Tomita, Hideki, Trautmann, Norbert, van Cleve, Shelley, Warbinek, Jessica, Wendt, Klaus, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Institut Laue-Langevin (ILL)

Subjects
Nuclear Physics - Experiment, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

International audience; We report on high-resolution laser spectroscopy studies on Cf249–253 with spectral linewidths in the order of 100 MHz carried out at the RISIKO mass separator at Mainz University. In total three atomic ground-state transitions were investigated and the hyperfine parameters for the odd-A isotopes and isotope shift for all examined isotopes have been determined from the measured spectra. The isotope shift measurements allowed tracking of changes in mean-squared charge radii across the deformed nuclear shell closure at N=152, whereby shape discontinuities were not observed. Experimental hyperfine coupling constants of the atomic ground state were combined with relativistic many-body atomic calculations to extract the nuclear magnetic-dipole moment of Cf249 with improved precision to μI(249Cf)=−0.395(17)μN, whereas μI(251Cf)=−0.571(24)μN and μI(253Cf)=−0.731(35)μN were derived for the first time. Additionally, the spectroscopic quadrupole moments QS(249Cf)=6.27(33)eb and QS(253Cf)=5.53(51)eb were extracted.

Published
2023
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14. Nuclear moments and isotope shifts of the actinide isotopes $^{249 – 253}$Cf probed by laser spectroscopy

Author

Weber, Felix, Albrecht-Schönzart, Thomas E., Gadelshin, Vadim, Goriely, Stephane, Harvey, Ashley, Heinke, Reinhard, Hilaire, Stephane, Kaja, Magdalena, Kieck, Tom, Kneip, Nina, Köster, Ulli, Lantis, Jeremy, Allehabi, Saleh O., Mokry, Christoph, Münzberg, Danny, Nothhelfer, Steven, Oberstedt, Stephan, Péru, Sophie, Raeder, Sebastian, Runke, Jörg, Sonnenschein, Volker, Stemmler, Matou, Studer, Dominik, Berndt, Sebastian, Thörle-Pospiech, Petra, Tomita, Hideki, Trautmann, Norbert, Van Cleve, Shelley, Warbinek, Jessica, Wendt, Klaus, Block, Michael, Dorrer, Holger, Düllmann, Christoph Emanuel, Dzuba, Vladimir A., Ezold, Julie G., and Flambaum, Victor V.

Subjects
ddc:530
Published
2023
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15. Actinide and lanthanide thin-layer developments using a drop-on-demand printing system

Author

Renisch, Dennis, Düllmann, Christoph E., Abrosimov, Roman, Eberhardt, Klaus, Kindler, Birgit, Lommel, Bettina, Lukacova, Jana, Mokry, Christoph, Oberstedt, Stephan, Pohjalainen, Ilkka, Runke, Jörg, Schwab, Tanyel, Sirleaf, Christopher, Schumann, D., Stodel, C., and Gott, M.

Subjects
aktinoidit, lantanoidit, actinides, lanthanides, drop-on-demand printing system, harvinaiset maametallit
Abstract

Actinide and lanthanide thin layers with specific requirements regarding thickness, homogeneity, chemical purity, mechanical stability, and backing properties are applied in a multitude of physics and chemistry experiments. A novel target preparation method, the so-called “Drop-on-Demand” (DoD) technique, based on a commercial nanoliter (nL) dispenser is applied since a few years in the Nuclear Chemistry unit at Johannes Gutenberg University Mainz. The wetting behaviour of the nL droplets on the substrate’s surface is a key parameter determining the spatial distribution of the deposited material after evaporation. By switching from aqueous to organic solvents as well as by substrate surface modifications, the wetting behaviour can be influenced. Recent investigations on this influence and applications of the DoD method are presented. The produced actinide deposits were characterized by optical and scanning electron microscopy, by α spectroscopy as well as by radiographic imaging. peerReviewed

Published
2023

16. Measurement of the fission yield of 136Cs in the 239Pu(nth,f) reaction.

Author

Chebboubi, Abdelaziz, Bernard, David, Vallet, Vanessa, Kessedjian, Grégoire, Méplan, Olivier, Kim, Yung Hee, Köster, Ulli, Géhin, Florian, Sage, Christophe, Ramdhane, Mourad, Houdouin-Quenault, Maxime, Düllmann, Christoph E., Mokry, Christoph, Runke, Jörg, Renisch, Dennis, Litaize, Olivier, and Serot, Olivier

Subjects
NUCLEAR fission, PLUTONIUM isotopes, NUCLEAR reactions, NUCLEAR reactors, VACUUM chambers
Abstract

A recent experimental campaign performed at the LOHENGRIN spectrometer at ILL aimed at measuring the independent fission yield of 136Cs in the 239Pu(nth,f) reaction. This nuclide can have an important contribution to the total dose rate coming from spent light water reactor UOX and MOX fuels. Moreover, its impact is of first order on the uncertainty of the total dose rate calculated in specific areas of Nuclear Power Plants within accidental conditions. One of the most important sources of uncertainty is its independent fission yield. Therefore, a new measurement of its independent yield along with a rigorous uncertainty analysis was performed. Due to its low independent yield, a new measurement technique has been applied. Ions recoiling from neutron-irradiated 239Pu target were collected by implantation into an Al foil placed inside a vacuum chamber. This foil was then transferred to a low γ-ray background setup located at nearby laboratory (LPSC). The procedure was then repeated for different LOHENGRIN settings. Compared to the JEFF-3.1.1 library, a decrease of the fission yield of 136Cs with a reduced uncertainty is obtained. [ABSTRACT FROM AUTHOR]

Published
2023
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17. Preparation and characterization of 239Pu and 240Pu recoil ion sources

Author

Reed, Lauren E., Raggio, Andrea, Renisch, Dennis, Block, Michael, Düllmann, Christoph E., Julin, Jaakko, Kivekäs, Mikko, Laitinen, Mikko, Mokry, Christoph, Moore, Iain D., Pohjalainen, Ilkka, Runke, Jörg, Sajavaara, Timo, Thörle-Pospiech, Petra, and Warbinek, Jessica

Abstract

Poster presentation given at LISA Summer School, Normandy, France, 29.08.22 – 9.09.22.

Published
2022
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18. Atomic-structure investigations of neutral einsteinium by laser resonance ionization

Author

Weber, Felix, primary, Albrecht-Schönzart, Thomas E., additional, Block, Michael, additional, Chhetri, Premaditya, additional, Düllmann, Christoph E., additional, Ezold, Julie G., additional, Gadelshin, Vadim, additional, Gaiser, Alyssa N., additional, Giacoppo, Francesca, additional, Heinke, Reinhard, additional, Kieck, Tom, additional, Kneip, Nina, additional, Laatiaoui, Mustapha, additional, Mokry, Christoph, additional, Nothhelfer, Steven, additional, Raeder, Sebastian, additional, Runke, Jöorg, additional, Schneider, Fabian, additional, Sperling, Joseph M., additional, Studer, Dominik, additional, Thörle-Pospiech, Petra, additional, Trautmann, Norbert, additional, and Wendt, Klaus, additional

Published
2022
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19. Preparation and characterization of Pu-239 recoil ion sources providing U-235m for laser-spectroscopic study

Author

Reed, Lauren E., Raggio, Andrea, Renisch, Dennis, Block, Michael, Düllmann, Christoph E., Julin, Jaakko, Kivekäs, Mikko, Laitinen, Mikko, Mokry, Christoph, Moore, Iain D., Pohjalainen, Ilkka, Runke, Jörg, Sajavaara, Timo, Thörle-Pospiech, Petra, and Warbinek, Jessica

Abstract

Presentation on preparation and characterization of Pu-239 recoil ion sources providing U-235m for laser-spectroscopic study given by L. E. Reed on 17.06.2022 for LISA academic day.

Published
2022
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20. Probing the Atomic Structure of Californium by Resonance Ionization Spectroscopy

Author

Weber, Felix, primary, Düllmann, Christoph Emanuel, additional, Gadelshin, Vadim, additional, Kneip, Nina, additional, Oberstedt, Stephan, additional, Raeder, Sebastian, additional, Runke, Jörg, additional, Mokry, Christoph, additional, Thörle-Pospiech, Petra, additional, Studer, Dominik, additional, Trautmann, Norbert, additional, and Wendt, Klaus, additional

Published
2022
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21. Nuclear structure invesitgations of 253-255Es by laser spectroscopy

Author

Nothhelfer, Steven, Albrecht-Schönzart, Thomas E., Block, Michael, Chhetri, Premaditya, Düllmann, Christoph E., Ezold, Julie G., Gadelshin, Vadim, Gaiser, Alyssa, Giacoppo, Francesca, Heinke, Reinhard, Kieck, Tom, Kneip, Nina, Laatiaoui, Mustapha, Mokry, Christoph, Raeder, Sebastian, Runke, Jörg, Schneider, Fabian, Sperling, Joseph M., Studer, Dominik, Thörle-Pospiech, Petra, Trautmann, Norbert, Weber, Felix, and Wendt, Klaus

Subjects
Electromagnetic moments, Isotope shift, Rare & new isotopes, Nuclear structure, Spectroscopic techniques, Nuclear spin & parity, Radioactive beams
Abstract

I am one of the LISA affiliates andhappy to announce my first publication in Phys. Rev. C(https://link.aps.org/doi/10.1103/PhysRevC.105.L021302) about nuclear structure investigations in the rare isotopes 253-255Es!

Published
2022

22. Direct detection of the 229Th nuclear clock transition

Author

von der Wense, Lars, Seiferle, Benedict, Laatiaoui, Mustapha, Neumayr, Jürgen B., Maier, Hans-Jörg, Wirth, Hans-Friedrich, Mokry, Christoph, Runke, Jörg, Eberhardt, Klaus, Düllmann, Christoph E., Trautmann, Norbert G., and Thirolf, Peter G.

Published
2016
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23. Gas phase synthesis of 4d transition metal carbonyl complexes with thermalized fission fragments in single-atom reactions

Author

Götz, Michael, primary, Götz, Stefan, additional, Kratz, Jens-Volker, additional, Ballof, Jochen, additional, Düllmann, Christoph E., additional, Eberhardt, Klaus, additional, Mokry, Christoph, additional, Renisch, Dennis, additional, Runke, Jörg, additional, Sato, Tetsuya K., additional, Thörle-Pospiech, Petra, additional, Trautmann, Norbert, additional, and Yakushev, Alexander, additional

Published
2021
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25. Measurement of the Th229 Isomer Energy with a Magnetic Microcalorimeter

Author

Sikorsky, Tomas, primary, Geist, Jeschua, additional, Hengstler, Daniel, additional, Kempf, Sebastian, additional, Gastaldo, Loredana, additional, Enss, Christian, additional, Mokry, Christoph, additional, Runke, Jörg, additional, Düllmann, Christoph E., additional, Wobrauschek, Peter, additional, Beeks, Kjeld, additional, Rosecker, Veronika, additional, Sterba, Johannes H., additional, Kazakov, Georgy, additional, Schumm, Thorsten, additional, and Fleischmann, Andreas, additional

Published
2020
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26. Chemical studies of Fl (element 114): Heaviest chemically studied element

Author

Lens, Lotte, Yakushev, Alexander, Duellmann, Christoph, Asai, Masato, Block, Michael, David, Helena May, Despotopulos, John D., Di Nitto, Antonio, Eberhardt, Klaus, Goetz, Michael, Goetz, Stefan, Haba, Hiromitsu, Harkness-Brennan, Laura, Hessberger, Fritz-Peter, Herzberg, Rolf-Dietmar, Hinde, David, Hoffmann, Jan, Annett, Huebner, Jaeger, Egon, Judson, Daniel, Jadambaa, Khuyagbaatar, Kindler, Birgit, Konki, Joonas, Kratz, Jens Volker, Krier, Jorg, Kurz, Nikolaus, Mustapha Laatiaoui, Lahiri, Susanta, Lommel, Bettina, Maiti, Momita, Mistry, Andrew K., Mokry, Christoph, Moody, Ken, Nagame, Yuichiro, Omtvedt, Jon, Papadakis, Philippos, Pershina, Valeria, Rudolph, Dirk, Runke, Joerg, Schaedel, Matthias, Scharrer, Paul, Sato, Tetsuya, Shaughnessy, Dawn, Schausten, Brigitta, Steiner, Jutta, Thoerle-Pospiech, Petra, Trautmann, Norbert, Tsukada, Kazuaki, Uusitalo, Juha, Ward, Andrew, Wegrzecki, Maciej, Williams, Elizabeth, Wiehl, Norbert, and Yakusheva, Vera

Published
2017

27. Alpha spectrometric characterization of thin 233U sources for 229(m)Th production.

Author

Haas, Raphael, Hufnagel, Michelle, Abrosimov, Roman, Düllmann, Christoph E., Krupp, Dominik, Mokry, Christoph, Renisch, Dennis, Runke, Jörg, and Scherer, Ulrich W.

Subjects
SILICON surfaces, PASSIVATION, ION sources, SCANNING electron microscopy, ALPHA rays
Abstract

Four different techniques were applied for the production of 233U alpha recoil ion sources, providing 229Th ions. They were compared with respect to a minimum energy spread of the 229Th recoil ions, using the emitted alpha particles as an indicator. The techniques of Molecular Plating, Drop-on-Demand inkjet printing, chelation from dilute nitric acid solution on chemically functionalized silicon surfaces, and self-adsorption on passivated titanium surfaces were used. All fabricated sources were characterized by using alpha spectrometry, radiographic imaging, and scanning electron microscopy. A direct validation for the estimated recoil ion rate was obtained by collecting 228Th recoil ions from 232U recoil ion sources prepared by self-adsorption and Molecular Plating. The chelation and the self-adsorption based approaches appear most promising for the preparation of recoil ion sources delivering monochromatic recoil ions. [ABSTRACT FROM AUTHOR]

Published
2020
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28. 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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29. Production, isolation and characterization of radiochemically pure 163Ho samples for the ECHo-project

Author

Dorrer, Holger, primary, Chrysalidis, Katerina, additional, Goodacre, Thomas Day, additional, Düllmann, Christoph E., additional, Eberhardt, Klaus, additional, Enss, Christian, additional, Gastaldo, Loredana, additional, Haas, Raphael, additional, Harding, Jonathan, additional, Hassel, Clemens, additional, Johnston, Karl, additional, Kieck, Tom, additional, Köster, Ulli, additional, Marsh, Bruce, additional, Mokry, Christoph, additional, Rothe, Sebastian, additional, Runke, Jörg, additional, Schneider, Fabian, additional, Stora, Thierry, additional, Türler, Andreas, additional, and Wendt, Klaus, additional

Published
2018
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31. Production, isolation and characterization of radiochemically pure 163Ho samples for the ECHo-project.

Author

Chrysalidis, Katerina, Eberhardt, Klaus, Haas, Raphael, Kieck, Tom, Mokry, Christoph, Schneider, Fabian, Wendt, Klaus, Dorrer, Holger, Düllmann, Christoph E., Harding, Jonathan, Türler, Andreas, Johnston, Karl, Marsh, Bruce, Stora, Thierry, Goodacre, Thomas Day, Rothe, Sebastian, Runke, Jörg, Enss, Christian, Gastaldo, Loredana, and Hassel, Clemens

Subjects
HOLMIUM isotopes, RADIOCHEMICAL separation, ELECTRON capture, NEUTRINO mass, PHASE separation, RARE earth metals
Abstract

Several experiments on the study of the electron neutrino mass are based on high-statistics measurements of the energy spectrum following electron capture of the radionuclide 163Ho. They rely on the availability of large, radiochemically pure samples of 163Ho. Here, we describe the production, separation, characterization, and sample production within the Electron Capture in Holmium-163 (ECHo) project. 163Ho has been produced by thermal neutron activation of enriched, prepurified 162Er targets in the high flux reactor of the Institut Laue-Langevin, Grenoble, France, in irradiations lasting up to 54 days. Irradiated targets were chemically processed by means of extraction chromatography, which allowed separating the formed Ho from the 162Er target-material and from the main byproducts 170Tm and 171Tm, which are co-produced in GBq amounts. Decontamination factors of >500 for Er and of >105 for Tm and yields of 3.6·1016 and 1.2·1018 atoms of 163Ho were obtained, corresponding to a recovery yield of 95 % of Ho in the chemical separation. The Ho-fraction was characterized by means of γ-ray spectrometry, Inductively-Coupled-Plasma Mass Spectrometry (ICP-MS), Resonance Ionization Mass Spectrometry (RIMS) and Neutron Activation Analysis (NAA). In this process, the thermal neutron capture cross section of 163Ho was measured to σHo-163 to Ho-164m= (23±3) b and σHo-163 to Ho-164g= (156±9) b for the formation of the two isomers of 164Ho. Specific samples were produced for further purification by mass separation to isolate 163Ho from the Ho-isotope mixture, as needed for obtaining the energy spectrum within ECHo. The partial efficiency for this second separation step is (32±5) %. [ABSTRACT FROM AUTHOR]

Published
2018
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32. 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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34. Measurement of the Th 229 Isomer Energy with a Magnetic Microcalorimeter

Author

Sikorsky, Tomas, Geist, Jeschua, Hengstler, Daniel, Kempf, Sebastian, Gastaldo, Loredana, Enss, Christian, Mokry, Christoph, Runke, Jörg, Düllmann, Christoph E., Wobrauschek, Peter, Beeks, Kjeld, Rosecker, Veronika, Sterba, Johannes H., Kazakov, Georgy, Schumm, Thorsten, and Fleischmann, Andreas

Subjects
ddc:530
Abstract

We present a measurement of the low-energy (0-60 keV) γ-ray spectrum produced in the α decay of ^{233}U using a dedicated cryogenic magnetic microcalorimeter. The energy resolution of ∼10 eV, together with exceptional gain linearity, allows us to determine the energy of the low-lying isomeric state in ^{229}Th using four complementary evaluation schemes. The most precise scheme determines the ^{229}Th isomer energy to be 8.10(17) eV, corresponding to 153.1(32) nm, superseding in precision previous values based on γ spectroscopy, and agreeing with a recent measurement based on internal conversion electrons. We also measure branching ratios of the relevant excited states to be b_{29}=9.3(6)% and b_{42}0.7%.

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35. 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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