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15 results on '"Kraemer, Sandro"'

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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3. Observation of the radiative decay of the ${}^{229}\mathrm{Th}$ nuclear clock isomer

Author

Kraemer, Sandro, Moens, Janni, Athanasakis-Kaklamanakis, Michail, Bara, Silvia, Beeks, Kjeld, Chhetri, Premaditya, Chrysalidis, Katerina, Claessens, Arno, Cocolios, Thomas E., Correia, João M., De Witte, Hilde, Ferrer, Rafael, Geldhof, Sarina, Heinke, Reinhard, Hosseini, Niyusha, Huyse, Mark, Köster, Ulli, Kudryavtsev, Yuri, Laatiaoui, Mustapha, Lica, Razvan, Magchiels, Goele, Manea, Vladimir, Merckling, Clement, Pereira, Lino M. C., Raeder, Sebastian, Schumm, Thorsten, Sels, Simon, Thirolf, Peter G., Tunhuma, Shandirai Malven, Bergh, Paul Van Den, Van Duppen, Piet, Vantomme, André, Verlinde, Matthias, Villarreal, Renan, and Wahl, Ulrich

Subjects
Nuclear Experiment
Abstract

The nucleus of the radioisotope thorium-229 (${}^{229}$Th) features an isomer with an exceptionally low excitation energy that enables direct laser manipulation of nuclear states. For this reason, it is a leading candidate for use in next-generation optical clocks. This nuclear clock will be a unique tool, amongst others, for tests of fundamental physics. While first indirect experimental evidence for the existence of such an extraordinary nuclear state is significantly older, the proof of existence has been delivered only recently by observing the isomer's electron conversion decay and its hyperfine structure in a laser spectroscopy study, revealing information on the isomer's excitation energy, nuclear spin and electromagnetic moments. Further studies reported the electron conversion lifetime and refined the isomer's energy. In spite of recent progress, the isomer's radiative decay, a key ingredient for the development of a nuclear clock, remained unobserved. In this Letter, we report the detection of the radiative decay of this low-energy isomer in thorium-229 (${}^{229\mathrm{m}}$Th). By performing vacuum-ultraviolet spectroscopy of ${}^{229\mathrm{m}}$Th incorporated into large-bandgap CaF${}_2$ and MgF${}_2$ crystals at the ISOLDE facility at CERN, the photon vacuum wavelength of the isomer's decay is measured as 148.71(42) nm, corresponding to an excitation energy of 8.338(24) eV. This value is in agreement with recent measurements, and decreases the uncertainty by a factor of seven. The half-life of ${}^{229\mathrm{m}}$Th embedded in MgF${}_2$ is determined to be 670(102) s. The observation of the radiative decay in a large-bandgap crystal has important consequences for the design of a future nuclear clock and the improved uncertainty of the energy eases the search for direct laser excitation of the atomic nucleus.

Published
2022
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4. Observation of the radiative decay of the 229Th nuclear clock isomer

Author

Kraemer, Sandro, Moens, Janni, Athanasakis-Kaklamanakis, Michail, Bara, Silvia, Beeks, Kjeld, Chhetri, Premaditya, Chrysalidis, Katerina, Claessens, Arno, Cocolios, Thomas E., Correia, João G. M., Witte, Hilde De, Ferrer, Rafael, Geldhof, Sarina, Heinke, Reinhard, Hosseini, Niyusha, Huyse, Mark, Köster, Ulli, Kudryavtsev, Yuri, Laatiaoui, Mustapha, Lica, Razvan, Magchiels, Goele, Manea, Vladimir, Merckling, Clement, Pereira, Lino M. C., Raeder, Sebastian, Schumm, Thorsten, Sels, Simon, Thirolf, Peter G., Tunhuma, Shandirai Malven, Van Den Bergh, Paul, Van Duppen, Piet, Vantomme, André, Verlinde, Matthias, Villarreal, Renan, and Wahl, Ulrich

Published
2023
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6. Opportunities and limitations of in-gas-cell laser spectroscopy of the heaviest elements with RADRIS

Author

Raeder, Sebastian, Anđelić, Brankica, Auler, Julian, Block, Michael, Chauveau, Pierre, Chhetri, Premaditya, Claessens, Arno, de Roubin, Antoine, Düllmann, Christoph E., Ferrer, Rafael, Giacoppo, Francesca, Gutiérrez, Manuel J., Heßberger, Fritz-Peter, Ivandikov, Fedor, Kaja, Magdalena, Kaleja, Oliver, Kieck, Tom, Kim, Eunkang, Kraemer, Sandro, Laatiaoui, Mustapha, Lantis, Jeremy, Lecesne, Nathalie, Moore, Iain D., Mistry, Andrew, Münzberg, Danny, Nothhelfer, Steven, Raggio, Andrea, Rey-Herme, Emmanuel, Rickert, Elisabeth, Romans, Jekabs, Romero-Romero, Elisa, Stemmler, Matou, Vandebrouck, Marine, Van Duppen, Piet, Walther, Thomas, Warbinek, Jessica, and Wendt, Klaus

Published
2023
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9. The ALPHATRAP experiment

Author

Sturm, Sven, Arapoglou, Ioanna, Egl, Alexander, Höcker, Martin, Kraemer, Sandro, Sailer, Tim, Tu, Bingsheng, Weigel, Andreas, Wolf, Robert, López-Urrutia, José Crespo, and Blaum, Klaus

Published
2019
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11. Setup for the Ionic Lifetime Measurement of the 229m Th 3+ Nuclear Clock Isomer.

Author

Scharl, Kevin, Ding, Shiqian, Holthoff, Georg, Hussain, Mahmood Irtiza, Kraemer, Sandro, Löbell, Lilli, Moritz, Daniel, Rozibakieva, Tamila, Seiferle, Benedict, Zacherl, Florian, and Thirolf, Peter G.

Subjects
CLOCKS & watches, ISOMERS, FREQUENCY standards, EXCITED states, DARK matter, CRYOGENICS
Abstract

For the realization of an optical nuclear clock, the first isomeric excited state of thorium-229 (229mTh) is currently the only candidate due to its exceptionally low-lying excitation energy ( 8.338 ± 0.024 eV). Such a nuclear clock holds promise not only to be a very precise metrological device but also to extend the knowledge of fundamental physics studies, such as dark matter research or variations in fundamental constants. Considerable progress was achieved in recent years in characterizing 229mTh from its first direct identification in 2016 to the only recent observation of the long-sought-after radiative decay channel. So far, nuclear resonance as the crucial parameter of a nuclear frequency standard has not yet been determined with laser-spectroscopic precision. To determine another yet unknown basic property of the thorium isomer and to further specify the linewidth of its ground-state transition, a measurement of the ionic lifetime of the isomer is in preparation. Theory and experimental investigations predict the lifetime to be 103–104 s. To precisely target this property using hyperfine structure spectroscopy, an experimental setup is currently being commissioned at LMU Munich. It is based on a cryogenic Paul trap providing long-enough storage times for 229mTh ions, that will be sympathetically cooled with 88Sr+. This article presents a concept for an ionic lifetime measurement and discusses the laser-optical part of a setup specifically developed for this purpose. [ABSTRACT FROM AUTHOR]

Published
2023
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12. Study of the radiative decay of the low-energy isomer in $^{229}$Th

Author

Chhetri, Premaditya, Bara, Silvia, Beeks, Kjeld, Bernerd, Cyril, Block, Michael, Claessens, Arno, Cocolios, Thomas Elias, Martins Correia, João Guilherme, Granadeiro Costa, Angelo Rafael, Cottenier, Stefaan, DE Witte, Hilde, Ferrer, Rafael, Geldhof, Sarina, Ivandikov, Fedor, Koudriavtsev, Yuri, Koester, Ulli, Kraemer, Sandro, Laatiaoui, Mustapha, Lica, Razvan, Magchiels, Goele, Moens, Janni, Moore, Iain, Pereira, Lino, Raeder, Sebastian, Reponen, Mikael, Rothe, Sebastian, de Roubin, Antoine, Schumm, Thorsten, Sels, Simon, Thirolf, Peter, Tunhuma, Shandirai Malven, Van Den Bergh, Paul, Van Duppen, Piet, Vantomme, André, Villarreal, Renan, and Wahl, Ulrich

Subjects
Detectors and Experimental Techniques
Published
2022

13. First Offline Results from the S3 Low-Energy Branch

Author

Romans, Jekabs, primary, Ajayakumar, Anjali, additional, Authier, Martial, additional, Boumard, Frederic, additional, Caceres, Lucia, additional, Cam, Jean-François, additional, Claessens, Arno, additional, Damoy, Samuel, additional, Delahaye, Pierre, additional, Desrues, Philippe, additional, Drouart, Antoine, additional, Duchesne, Patricia, additional, Ferrer, Rafael, additional, Fléchard, Xavier, additional, Franchoo, Serge, additional, Gangnant, Patrice, additional, de Groote, Ruben P., additional, Kraemer, Sandro, additional, Lecesne, Nathalie, additional, Leroy, Renan, additional, Lory, Julien, additional, Lutton, Franck, additional, Manea, Vladimir, additional, Merrer, Yvan, additional, Moore, Iain, additional, Ortiz-Cortes, Alejandro, additional, Osmond, Benoit, additional, Piot, Julien, additional, Pochon, Olivier, additional, Retailleau, Blaise-Maël, additional, Savajols, Hervé, additional, Sels, Simon, additional, Traykov, Emil, additional, Uusitalo, Juha, additional, Vandamme, Christophe, additional, Vandebrouck, Marine, additional, Van den Bergh, Paul, additional, Van Duppen, Piet, additional, Verlinde, Matthias, additional, Verstraelen, Elise, additional, and Wendt, Klaus, additional

Published
2022
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14. Study of the radiative decay of the low-energy isomer in ${}^{229}$Th

Author

Kraemer, Sandro, Beeks, Kjeld, Block, Michael, Cocolios, Thomas, Correia, Guilherme, Cottenier, Stefaan, De Witte, Hilde, Dockx, Kristof, Ferrer, Rafael, Geldhof, Sarina, Köster, Ulli, Laatiaoui, Mustapha, Lica, Razvan, Lin, Pin, Manea, Vladimir, Moens, Janni, Moore, Iain, Pereira, Lino, Raeder, Sebastian, Reponen, Mikael, Rothe, Sebastian, Schumm, Thorsten, Seiferle, Benedict, Sels, Simon, Thirolf, Peter, Van Den Bergh, Paul, Van Duppen, Piet, Vantomme, André, Verlinde, Matthias, Verstraelen, Elise, and Wahl, Ulrich

Subjects
Detectors and Experimental Techniques
Published
2020

15. First Offline Results from the S 3 Low-Energy Branch.

Author

Romans, Jekabs, Ajayakumar, Anjali, Authier, Martial, Boumard, Frederic, Caceres, Lucia, Cam, Jean-François, Claessens, Arno, Damoy, Samuel, Delahaye, Pierre, Desrues, Philippe, Drouart, Antoine, Duchesne, Patricia, Ferrer, Rafael, Fléchard, Xavier, Franchoo, Serge, Gangnant, Patrice, de Groote, Ruben P., Kraemer, Sandro, Lecesne, Nathalie, and Leroy, Renan

Subjects
NUCLEAR spectroscopy, LASER pumping, LASER measurement, ATOMIC spectroscopy, EXOTIC nuclei, PENNING trap mass spectrometry
Abstract

We present the first results obtained from the S 3 Low-Energy Branch, the gas cell setup at SPIRAL2-GANIL, which will be installed behind the S 3 spectrometer for atomic and nuclear spectroscopy studies of exotic nuclei. The installation is currently being commissioned offline, with the aim to establish optimum conditions for the operation of the radio frequency quadrupole ion guides, mass separation and ion bunching, providing high-efficiency and low-energy spatial spread for the isotopes of interest. Transmission and mass-resolving power measurements are presented for the different components of the S 3 -LEB setup. In addition, a single-longitudinal-mode, injection-locked, pumped pulsed-titanium–sapphire laser system has been recently implemented and is used for the first proof-of-principle measurements in an offline laser laboratory. Laser spectroscopy measurements of erbium, which is the commissioning case of the S 3 spectrometer, are presented using the 4 f 12 6 s 2 3 H 6 → 4 f 12 (3 H) 6 s 6 p optical transition. [ABSTRACT FROM AUTHOR]

Published
2022
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