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37 results on '"Oberstedt A"'

1. Determination of the Plasma Delay Time in PIPS detectors for fission fragments at the LOHENGRIN spectrometer

Author

Gómez Ana M., Al-Adili Ali, Göök Alf, Pomp Stephan, Pousette André, Solders Andreas, Tarrío Diego, Gao Zhihao, Köster Ulli, Kim Yung Hee, Smith A. Gavin, Sosnin Nikolay V., Bennett Samuel, Wright Tobias, Oberstedt Andreas, and Oberstedt Stephan

Subjects
Physics, QC1-999
Abstract

The VElocity foR Direct particle Identification spectrometer (VERDI) is a 2E-2v fission spectrometer that allows the measurement of the total mass distribution of secondary fission fragments with a resolving power of 1-2 u. It consists of two time-of-flight (ToF) arms, with one Micro Channel Plate (MCP) detector and up to 32 Silicon PIPS (Passive Implanted Planar Silicon) detectors per arm. The MCPs provide the start timing signals and the PIPS detectors provide both the energy and the stopping ToF signals. In real conditions, the PIPS signals are affected by the formation of plasma from the interaction between the heavy ions and the detector material. The plasma contributes to a reduction in signal amplitude, resulting in a Pulse Height Defect (PHD), and introduces a signal delay, known as Plasma Delay Time (PDT). An experiment to characterize the PDT and PHD was performed at the LOHENGRIN recoil separator of the Institut Laue Langevin (ILL). Characteristic fission fragments from the 239Pu(n,f) reaction were separated based on their A/Q and E/Q ratios, allowing the measurement of a wide range of energies from 21 to 110 MeV and masses between 80 and 149 u. Six PIPS detectors were characterized to study their individual responses to the PDT and PHD effects. The signals were recorded in a digital acquisition system to completely exploit the offline analysis capabilities. Achieved combined timing and energy resolutions for fission fragments varied between 72(2) ps and 100(4) ps and 1.4% - 2% (FWHM), respectively. Preliminary PHD and PDT data are presented from the masses A=85, 95, 130 and 143. The PHD trends are strongly correlated with both the ion energy and mass. The PDT, on the other hand, shows a strong variation as a function of the ion kinetic energy but a smaller dependence on the ion mass.

Published
2023
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2. Characterization of isomers produced by the spontaneous fission of ${}^{252}$Cf with the VESPA setup

Author

Piau, V., Göök, A., Oberstedt, S., Oberstedt, A., Chebboubi, A., Litaize, O., and Vidali, M.

Subjects
Nuclear Experiment
Abstract

Isomers produced by spontaneous fission of ${}^{252}$Cf have been measured with the VESPA setup, composed of LaBr$_3$(Ce) detectors for fast $\gamma$-ray spectroscopy and an ionization chamber for detecting fission fragments. Identification of the isomers was derived from fission fragment-$\gamma$-$\gamma$ coincidences. This paper presents the half-life of 34 isomeric states measured with this setup, from less than the nanosecond up to tens of microseconds. Two of these isomers are reported for the first time, in ${}^{108}$Tc and ${}^{147}$Ce. In addition to this half-life analysis, the isomers are used to develop and test a nuclear charge calibration of the ionization chamber.

Published
2024
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3. Increasing the rate capability for the cryogenic stopping cell of the FRS Ion Catcher

Author

Zhao, J. W., Amanbayev, D., Dickel, T., Miskun, I., Plass, W. R., Tortorelli, N., Andres, S. Ayet San, Beck, Soenke, Bergmann, J., Brencic, Z., Constantin, P., Geissel, H., Greiner, F., Groef, L., Hornung, C., Kuzminzuk, N., Kripko-Koncz, G., Mardor, I., Pohjalainen, I., Scheidenberger, C., Thirolf, P. G., Bagchi, S., Haettner, E., Kazantseva, E., Kostyleva, D., Oberstedt, A., Pietri, S., Reiter, M. P., Tanaka, Y. K., Wada, M., Balabanski, D. L., Benyaming, D., Harakeh, M. N., Hubbard, N., Kalantar-Nayestanaki, N., Mollaebrahimi, A., Mukhab, I., Narang, M., Niwasel, T., Patyk, Z., Purushothaman, S., Rotaru, A., Spataruf, A., Stanico, G., Vencelje, M., Weickb, H., Yu, J., and Collaboration, the Super-FRS Experiment

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

At the FRS Ion Catcher (FRS-IC), projectile and fission fragments are produced at relativistic energies, separated in-flight, energy-bunched, slowed down, and thermalized in the ultra-pure helium gas-filled cryogenic stopping cell (CSC). Thermalized nuclei are extracted from the CSC using a combination of DC and RF electric fields and gas flow. This CSC also serves as the prototype CSC for the Super-FRS, where exotic nuclei will be produced at unprecedented rates making it possible to go towards the extremes of the nuclear chart. Therefore, it is essential to efficiently extract thermalized exotic nuclei from the CSC under high beam rate conditions, in order to use the rare exotic nuclei which come as cocktail beams. The extraction efficiency dependence on the intensity of the impinging beam into the CSC was studied with a primary beam of 238U and its fragments. Tests were done with two different versions of the DC electrode structure inside the cryogenic chamber, the standard 1 m long and a short 0.5 m long DC electrode. In contrast to the rate capability of 10^4 ions/s with the long DC electrode, results show no extraction efficiency loss up to the rate of 2x10^5 ions/s with the new short DC electrode. This order of magnitude increase of the rate capability paves the way for new experiments at the FRS-IC, including exotic nuclei studies with in-cell multi-nucleon transfer reactions. The results further validate the design concept of the CSC for the Super-FRS, which was developed to effectively manage beams of even higher intensities.

Published
2023

5. Constraints on partial half-lives of Ce136 and Ce138 double electron captures

Author

Lehnert, B, Hult, M, Lutter, G, Marissens, G, Oberstedt, S, Stroh, H, Kotila, J, Oberstedt, A, and Zuber, K

Subjects
Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract

The γ-ray emissions from a radiopure cerium-bromide crystal with a mass of 4381 g were measured for a total of 497.4 d by means of high-resolution γ-ray spectrometry in the HADES underground laboratory at a depth of 500 m.w.e. A search for 0/2νϵϵ and 0/2νϵβ+ double beta decay transitions of Ce136 and Ce138 was performed using Bayesian analysis techniques. No signals were observed for a total of 35 investigated decay modes. 90% credibility limits were set in the order of 1018-1019 yr. Existing constraints from a cerium oxide powder measurement were tested with a different cerium compound and half-life limits could be improved for most of the decay modes. The most likely accessible decay mode of the Ce136 2νϵϵ transition into the 01+ state of Ba136 results in a new best 90% credibility limit of 5.0×1018 yr.

Published
2022

8. Increasing the rate capability for the cryogenic stopping cell of the FRS Ion Catcher

Author

Zhao, J.W., Amanbayev, D., Dickel, T., Miskun, I., Plaß, W.R., Tortorelli, N., San Andrés, S. Ayet, Beck, S., Bergmann, J., Brencic, Z., Constantin, P., Geissel, H., Greiner, F., Gröf, L., Hornung, C., Kuzminchuk, N., Kripkó-Koncz, G., Mardor, I., Pohjalainen, I., Scheidenberger, C., Thirolf, P.G., Bagchi, S., Haettner, E., Kazantseva, E., Kostyleva, D., Oberstedt, A., Pietri, S., Reiter, M.P., Tanaka, Y.K., Wada, M., Balabanski, D.L., Benyamin, D., Harakeh, M.N., Hubbard, N., Kalantar-Nayestanaki, N., Mollaebrahimi, A., Mukha, I., Narang, M., Niwase, T., Patyk, Z., Purushothaman, S., Rotaru, A., Spǎtaru, A., Stanic, G., Vencelj, M., Weick, H., and Yu, J.

Published
2024
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9. Study of N=50Z=3282 gap evolution around N=50Z=3282: new structure information for N=50Z=3282Ge

Author

Thisse, D., Lebois, M., Verney, D., Wilson, J. N., Jovančević, N., Rudigier, M., Canavan, R., Etasse, D., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Oryńczak, N., Courtin, S., Cortés, M. L., Davies, P., Delafosse, C., Fallot, M., Fornal, B., Fraile, L., Gjestvang, D., Gottardo, A., Guadilla, V., Gerst, R. -B., Häfner, G., Hauschild, K., Heine, M., Henrich, C., Homm, I., Hommet, J., Ibrahim, F., Iskra, Ł. W., Ivanov, P., Jazrawi, S., Korgul, A., Koseoglou, P., Kröll, T., Kurtukian-Nieto, T., Meur, L. Le, Leoni, S., Ljungvall, J., Lopez-Martens, A., Lozeva, R., Matea, I., Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa-Silkowska, M., Poklepa, W., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Reygadas-Tello, D., Rezynkina, K., Sánchez-Tembleque, V., Siem, S., Schmitt, C., Söderström, P. -A., Solak, K., Sürder, C., Tocabens, G., Vedia, V., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M., Zeiser, F., and Ziliani, S.

Published
2023
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10. Medical radionuclide research activities at JRC-Geel

Author

Tsinganis Andrea, Crespo Pablo Serra, Plompen Arjan, Heyse Jan, Oberstedt Stephan, Moreno Ana Ruiz, and Fumagalli Francesco

Subjects
Physics, QC1-999
Abstract

A programme to study photon- and neutron-induced reactions of medical interest, as well as accelerator-based methods of medical radionuclide production, has been instituted at JRC-Geel, making use of both existing and new infrastructure. A new electron beamline that can deliver quasi-monoenergetic beams has been commissioned at the GELINA electron linac and will be primarily dedicated to the study of photonuclear reactions and for medical radioisotope production studies via photon irradiation. The recently renewed MONNET 3.5 MV Tandem accelerator provides light ion beams for reactionbased quasi-mono-energetic neutron production and has been used for the study of 99Mo production via neutron irradiation of molybdenum nanoparticles. In this work we present an overview of the medical radionuclide activities at JRCGeel, with particular attention to aspects of the design, development and operational challenges of the new GELINA electron beamline. Some future perspectives of the programme are also discussed.

Published
2024
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11. Measurement of 242Pu(n,f) in the 1-2 MeV energy range

Author

Mathieu Ludovic, Aïche Mourad, Marini Paola, Bouland Olivier, Chatel Carole, Czajkowski Serge, Kattikat-Melcom Deby, Kurtukian Teresa, Oberstedt Stephan, and Tsekhanovich Igor

Subjects
Physics, QC1-999
Abstract

The design of new generation fast nuclear reactors requires highly accurate cross-section measurements in the MeV energy region. The 242Pu fission cross section is of particular interest for Pu incineration and nuclear waste production. There are discrepancies around 1 MeV incident neutron energy between libraries and among experimental data. Some data suggest the presence of a strong structure between 1 and 1.2 MeV whereas it is barely visible on some other data and its shape is very different among evaluations. The large majority of the 242Pu(n,f) measurements have been carried out with respect to the 235U(n,f) secondary-standard cross section. This introduces a strong correlation between measurements from different research teams. Moreover, this reference cross section exhibits structures, in particular a steep increase of +10% at 1 MeV. Therefore, we aim to re-measure the 242Pu(n,f) cross section relative to the primary-standard 1H(n,n)p cross section, by using a proton recoil detector. This standard has a very high accuracy (0.4%), is not used for other 242Pu measurements, and is structureless. An experiment has been carried out in October 2022 at the MONNET facility in JRC Geel, with incident neutron energies from 0.9 MeV to 2.0 MeV. The experimental setup will be presented, and the analysis procedure will be detailed.

Published
2024
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12. Neutron and gamma multiplicities calculated in the consistent framework of the Hauser-Feshbach Monte Carlo code FIFRELIN

Author

Piau, V., Litaize, O., Chebboubi, A., Oberstedt, S., Göök, Alf, Oberstedt, A., Piau, V., Litaize, O., Chebboubi, A., Oberstedt, S., Göök, Alf, and Oberstedt, A.

Abstract

Monte-Carlo simulations to calculate the number of prompt particles emitted during fission were performed using the FIFRELIN code and compared to recent experimental data. We show that we are able to reproduce both the neutron and gamma-ray multiplicity distributions as a function of the pre-neutron mass of the fission fragments using a single consistent set of parameters. This result was made possible by using an energy-dependent spin cut-off model, driving the initial total angular momentum of the fission fragments, together with microscopic level densities from the HFB plus combinatorial method. We also discuss, how the initial excitation-energy sharing shapes the TKE-dependent gamma-ray multiplicity.(c) 2022 French Alternative Energies and Atomic Energy Commission (CEA). Published by Elsevier B.V.This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.

Published
2023
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13. Determination of the Plasma Delay Time in PIPS detectors for fission fragments at the LOHENGRIN spectrometer

Author

Gomez L, Ana Maria, Al-Adili, Ali, Göök, Alf, Pomp, Stephan, Pousette, André, Solders, Andreas, Tarrío, Diego, Gao, Zhihao, Köster, Ulli, Kim, Yung Hee, Smith, A. Gavin, Sosnin, Nikolay V., Bennett, Samuel, Wright, Tobias, Oberstedt, Andreas, Oberstedt, Stephan, Gomez L, Ana Maria, Al-Adili, Ali, Göök, Alf, Pomp, Stephan, Pousette, André, Solders, Andreas, Tarrío, Diego, Gao, Zhihao, Köster, Ulli, Kim, Yung Hee, Smith, A. Gavin, Sosnin, Nikolay V., Bennett, Samuel, Wright, Tobias, Oberstedt, Andreas, and Oberstedt, Stephan

Abstract

The VElocity foR Direct particle Identification spectrometer (VERDI) is a 2E-2v fission spectrometer that allows the measurement of the total mass distribution of secondary fission fragments with a resolving power of 1-2 u. It consists of two time-of-flight (ToF) arms, with one Micro Channel Plate (MCP) detector and up to 32 Silicon PIPS (Passive Implanted Planar Silicon) detectors per arm. The MCPs provide the start timing signals and the PIPS detectors provide both the energy and the stopping ToF signals. In real conditions, the PIPS signals are affected by the formation of plasma from the interaction between the heavy ions and the detector material. The plasma contributes to a reduction in signal amplitude, resulting in a Pulse Height Defect (PHD), and introduces a signal delay, known as Plasma Delay Time (PDT). An experiment to characterize the PDT and PHD was performed at the LOHENGRIN recoil separator of the Institut Laue Langevin (ILL). Characteristic fission fragments from the 239Pu(n,f) reaction were separated based on their A/Q and E/Q ratios, allowing the measurement of a wide range of energies from 21 to 110 MeV and masses between 80 and 149 u. Six PIPS detectors were characterized to study their individual responses to the PDT and PHD effects. The signals were recorded in a digital acquisition system to completely exploit the offline analysis capabilities. Achieved combined timing and energy resolutions for fission fragments varied between 72(2) ps and 100(4) ps and 1.4% - 2% (FWHM), respectively. Preliminary PHD and PDT data are presented from the masses A=85, 95, 130 and 143. The PHD trends are strongly correlated with both the ion energy and mass. The PDT, on the other hand, shows a strong variation as a function of the ion kinetic energy but a smaller dependence on the ion mass.

Published
2023
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14. New results in the modeling of fission and radiative neutron capture with FIFRELIN

Author

Litaize, Olivier, Piau, Valentin, Chalil, Achment, Ogawa, Tatsuhiko, Chebboubi, Abdel, Göök, Alf, Gunsing, Franck, Kessedjian, Gregoire, Lhuillier, David, Mancusi, Davide, Materna, Thomas, Oberstedt, Andreas, Oberstedt, Stephan, Serot, Olivier, Thulliez, Loic, Litaize, Olivier, Piau, Valentin, Chalil, Achment, Ogawa, Tatsuhiko, Chebboubi, Abdel, Göök, Alf, Gunsing, Franck, Kessedjian, Gregoire, Lhuillier, David, Mancusi, Davide, Materna, Thomas, Oberstedt, Andreas, Oberstedt, Stephan, Serot, Olivier, and Thulliez, Loic

Abstract

The FIFRELIN Monte Carlo code has been upgraded recently by adding new capabilities, additional models and updated databases. Several examples are presented in this work as well as three different applications related to the prompt component in fission, gamma cascades from thermal neutron capture and the delayed component in fission associated to the time evolution of decay heat.

Published
2023
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17. Examination of how properties of a fissioning system impact isomeric yield ratios of the fragments

Author

Gjestvang, D., primary, Wilson, J. N., additional, Al-Adili, A., additional, Siem, S., additional, Gao, Z., additional, Randrup, J., additional, Thisse, D., additional, Lebois, M., additional, Jovančević, N., additional, Canavan, R., additional, Rudigier, M., additional, Étasse, D., additional, Gerst, R.-B., additional, Adamska, E., additional, Adsley, P., additional, Algora, A., additional, Belvedere, C., additional, Benito, J., additional, Benzoni, G., additional, Blazhev, A., additional, Boso, A., additional, Bottoni, S., additional, Bunce, M., additional, Chakma, R., additional, Cieplicka-Oryńczak, N., additional, Courtin, S., additional, Cortés, M. L., additional, Davies, P., additional, Delafosse, C., additional, Fallot, M., additional, Fornal, B., additional, Fraile, L., additional, Gottardo, A., additional, Guadilla, V., additional, Häfner, G., additional, Hauschild, K., additional, Heine, M., additional, Henrich, C., additional, Homm, I., additional, Ibrahim, F., additional, Iskra, Ł. W., additional, Ivanov, P., additional, Jazrawi, S., additional, Korgul, A., additional, Koseoglou, P., additional, Kröll, T., additional, Kurtukian-Nieto, T., additional, Leoni, S., additional, Ljungvall, J., additional, Lopez-Martens, A., additional, Lozeva, R., additional, Matea, I., additional, Miernik, K., additional, Nemer, J., additional, Oberstedt, S., additional, Paulsen, W., additional, Piersa-Siłkowska, M., additional, Popovitch, Y., additional, Porzio, C., additional, Qi, L., additional, Regan, P. H., additional, Rezynkina, K., additional, Sánchez-Tembleque, V., additional, Schmitt, C., additional, Söderström, P.-A., additional, Sürder, C., additional, Tocabens, G., additional, Vedia, V., additional, Verney, D., additional, Warr, N., additional, Wasilewska, B., additional, Wiederhold, J., additional, Yavahchova, M., additional, and Ziliani, S., additional

Published
2023
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18. Measurement of 242Pu(n,f) in the 1-2 MeV energy range.

Author

Mathieu, Ludovic, Aïche, Mourad, Marini, Paola, Bouland, Olivier, Chatel, Carole, Czajkowski, Serge, Kattikat-Melcom, Deby, Kurtukian, Teresa, Oberstedt, Stephan, and Tsekhanovich, Igor

Subjects
NUCLEAR energy, NUCLEAR reactors, NUCLEAR cross sections, NEUTRON temperature, NEUTRON scattering measurement
Abstract

The design of new generation fast nuclear reactors requires highly accurate cross-section measurements in the MeV energy region. The 242Pu fission cross section is of particular interest for Pu incineration and nuclear waste production. There are discrepancies around 1 MeV incident neutron energy between libraries and among experimental data. Some data suggest the presence of a strong structure between 1 and 1.2 MeV whereas it is barely visible on some other data and its shape is very different among evaluations. The large majority of the 242Pu(n,f) measurements have been carried out with respect to the 235U(n,f) secondary-standard cross section. This introduces a strong correlation between measurements from different research teams. Moreover, this reference cross section exhibits structures, in particular a steep increase of +10% at 1 MeV. Therefore, we aim to re-measure the 242Pu(n,f) cross section relative to the primary-standard 1H(n,n)p cross section, by using a proton recoil detector. This standard has a very high accuracy (0.4%), is not used for other 242Pu measurements, and is structureless. An experiment has been carried out in October 2022 at the MONNET facility in JRC Geel, with incident neutron energies from 0.9 MeV to 2.0 MeV. The experimental setup will be presented, and the analysis procedure will be detailed. [ABSTRACT FROM AUTHOR]

Published
2024
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19. Probing the Atomic Structure of Californium by Resonance Ionization Spectroscopy

Author

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

Subjects
californium, resonance ionization spectroscopy, ionization potential, atomic structure, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The atomic structure of californium is probed by two-step resonance ionization spectroscopy. Using samples with a total amount of about 2×1010 Cf atoms (ca. 8.3 pg), ground-state transitions as well as transitions to high-lying Rydberg states and auto-ionizing states above the ionization potential are investigated and the lifetimes of various atomic levels are measured. These investigations lead to the identification of efficient ionization schemes, important for trace analysis and nuclear structure investigations. Most of the measurements are conducted on 250Cf. In addition, the isotope shift of the isotopic chain 249−252Cf is measured for one transition. The identification and analysis of Rydberg series enables the determination of the first ionization potential of californium to EIP=50,666.76(5)cm−1. This is about a factor of 20 more precise than the current literature value.

Published
2022
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20. Study of $$N=50$$ gap evolution around $$Z=32$$: new structure information for $${}^{82}$$Ge

Author

Thisse, D., primary, Lebois, M., additional, Verney, D., additional, Wilson, J. N., additional, Jovančević, N., additional, Rudigier, M., additional, Canavan, R., additional, Etasse, D., additional, Adsley, P., additional, Algora, A., additional, Babo, M., additional, Belvedere, K., additional, Benito, J., additional, Benzoni, G., additional, Blazhev, A., additional, Boso, A., additional, Bottoni, S., additional, Bunce, M., additional, Chakma, R., additional, Cieplicka-Oryńczak, N., additional, Courtin, S., additional, Cortés, M. L., additional, Davies, P., additional, Delafosse, C., additional, Fallot, M., additional, Fornal, B., additional, Fraile, L., additional, Gjestvang, D., additional, Gottardo, A., additional, Guadilla, V., additional, Gerst, R. -B., additional, Häfner, G., additional, Hauschild, K., additional, Heine, M., additional, Henrich, C., additional, Homm, I., additional, Hommet, J., additional, Ibrahim, F., additional, Iskra, Ł. W., additional, Ivanov, P., additional, Jazrawi, S., additional, Korgul, A., additional, Koseoglou, P., additional, Kröll, T., additional, Kurtukian-Nieto, T., additional, Meur, L. Le, additional, Leoni, S., additional, Ljungvall, J., additional, Lopez-Martens, A., additional, Lozeva, R., additional, Matea, I., additional, Miernik, K., additional, Nemer, J., additional, Oberstedt, S., additional, Paulsen, W., additional, Piersa-Silkowska, M., additional, Poklepa, W., additional, Popovitch, Y., additional, Porzio, C., additional, Qi, L., additional, Ralet, D., additional, Regan, P. H., additional, Reygadas-Tello, D., additional, Rezynkina, K., additional, Sánchez-Tembleque, V., additional, Siem, S., additional, Schmitt, C., additional, Söderström, P. -A., additional, Solak, K., additional, Sürder, C., additional, Tocabens, G., additional, Vedia, V., additional, Warr, N., additional, Wasilewska, B., additional, Wiederhold, J., additional, Yavahchova, M., additional, Zeiser, F., additional, and Ziliani, S., additional

Published
2023
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21. New results in the modeling of fission and radiative neutron capture with FIFRELIN

Author

Litaize, Olivier, primary, Piau, Valentin, additional, Chalil, Achment, additional, Ogawa, Tatsuhiko, additional, Chebboubi, Abdel, additional, Göök, Alf, additional, Gunsing, Franck, additional, Kessedjian, Grégoire, additional, Lhuillier, David, additional, Mancusi, Davide, additional, Materna, Thomas, additional, Oberstedt, Andreas, additional, Oberstedt, Stephan, additional, Serot, Olivier, additional, and Thulliez, Loïc, additional

Published
2023
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23. Examination of how properties of a fissioning system impact isomeric yield ratios of the fragments

Author

Gjestvang, D., Wilson, J. N., Al-Adili, Ali, Siem, S., Gao, Zhihao, Randrup, J., Thisse, D., Lebois, M., Jovancevic, N., Canavan, R., Rudigier, M., Etasse, D., Gerst, R. -b., Adamska, E., Adsley, P., Algora, A., Belvedere, C., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Courtin, S., Cortes, M. L., Davies, P., Delafosse, C., Fallot, M., Fornal, B., Fraile, L., Gottardo, A., Guadilla, V., Hafner, G., Hauschild, K., Heine, M., Henrich, C., Homm, I., Ibrahim, F., Iskra, L. W., Ivanov, P., Jazrawi, S., Korgul, A., Koseoglou, P., Kroll, T., Kurtukian-Nieto, T., Leoni, S., Ljungvall, J., Lopez-Martens, A., Lozeva, R., Matea, I., Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa-Silkowska, M., Popovitch, Y., Porzio, C., Qi, L., Regan, P. H., Rezynkina, K., Sanchez-Tembleque, V., Schmitt, C., Soderstrom, P. -a., Surder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M., Ziliani, S., Gjestvang, D., Wilson, J. N., Al-Adili, Ali, Siem, S., Gao, Zhihao, Randrup, J., Thisse, D., Lebois, M., Jovancevic, N., Canavan, R., Rudigier, M., Etasse, D., Gerst, R. -b., Adamska, E., Adsley, P., Algora, A., Belvedere, C., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Courtin, S., Cortes, M. L., Davies, P., Delafosse, C., Fallot, M., Fornal, B., Fraile, L., Gottardo, A., Guadilla, V., Hafner, G., Hauschild, K., Heine, M., Henrich, C., Homm, I., Ibrahim, F., Iskra, L. W., Ivanov, P., Jazrawi, S., Korgul, A., Koseoglou, P., Kroll, T., Kurtukian-Nieto, T., Leoni, S., Ljungvall, J., Lopez-Martens, A., Lozeva, R., Matea, I., Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa-Silkowska, M., Popovitch, Y., Porzio, C., Qi, L., Regan, P. H., Rezynkina, K., Sanchez-Tembleque, V., Schmitt, C., Soderstrom, P. -a., Surder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M., and Ziliani, S.

Abstract

The population of isomeric states in the prompt decay of fission fragments-so-called isomeric yield ratios (IYRs)-is known to be sensitive to the angular momentum J that the fragment emerged with, and may therefore contain valuable information on the mechanism behind the fission process. In this work, we investigate how changes in the fissioning system impact the measured IYRs of fission fragments to learn more about what parameters affect angular momentum generation. To enable this, a new technique for measuring IYRs is first demonstrated. It is based on the time of arrival of discrete gamma rays, and has the advantage that it enables the study of the IYR as a function of properties of the partner nucleus. This technique is used to extract the IYR of 134Te, strongly populated in actinide fission, from the three different fissioning systems: 232Th(n, f), 238U(n, f), at two different neutron energies, as well as 252Cf(sf). The impacts of changing the fissioning system, the compound nuclear excitation energy, the minimum J of the binary partner, and the number of neutrons emitted on the IYR of 134Te are determined. The decay code TALYS is used in combination with the fission simulation code FREYA to calculate the primary fragment angular momentum from the IYR. We find that the IYR of 134Te has a slope of 0.004 +/- 0.002 with increase in compound nucleus (CN) mass. When investigating the impact on the IYR of increased CN excitation energy, we find no change with an energy increase similar to the difference between thermal and fast fission. By varying the mass of the partner fragment emerging with 134Te, it is revealed that the IYR of 134Te is independent of the total amount of prompt neutrons emitted from the fragment pair. This indicates that neutrons carry minimal angular momentum away from the fission fragments. Comparisons with the FREYA+TALYS simulations reveal that the average angular momentum in 134Te following 238U(n, f) is 6.0 h over bar . This is not consiste

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

Author

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

Published
2023
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26. 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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27. 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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28. 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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29. 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

30. Actinide and lanthanide thin-layer developments using a drop-on-demand printing system

Author

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

Published
2023
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33. Constraints on partial half-lives of Ce136 and Ce138 double electron captures

Author

Lehnert, B., Hult, M., Lutter, G., Marissens, G., Oberstedt, S., Stroh, H., Kotila, J., Oberstedt, A., and Zuber, K.

Subjects
Particle and Plasma Physics, FOS: Physical sciences, Molecular, Nuclear, Nuclear Experiment (nucl-ex), Nuclear Experiment, Atomic, Nuclear & Particles Physics
Abstract

The gamma-ray emissions from a radiopure cerium-bromide crystal with a mass of 4381 g were measured for a total of 497.4 d by means of high-resolution gamma-ray spectrometry in the HADES underground laboratory at a depth of 500 m.w.e. A search for 0/2nee and 0/2neb+ double beta decay transitions of Ce-136 and Ce-138 was performed using Bayesian analysis techniques. No signals were observed for a total of 35 investigated decay modes. 90% credibility limits were set in the order of 1e18-1e19 a. Existing constraints from a cerium oxide powder measurement were tested with a different cerium compound and half-life limits could be improved for most of the decay modes. The most likely accessible decay mode of the Ce-136 2nee transition into the 0+1 state of Ba-136 results in a new best 90% credibility limit of 5.0e18 a.

Published
2022

34. Neutron and gamma multiplicities calculated in the consistent framework of the Hauser-Feshbach Monte Carlo code FIFRELIN

Author

V. Piau, O. Litaize, A. Chebboubi, S. Oberstedt, A. Göök, and A. Oberstedt

Subjects
Subatomär fysik, Nuclear and High Energy Physics, ?-ray multiplicity, Subatomic Physics, Nuclear fission, Nuclear level densities, Monte Carlo, Fragment de-excitation
Abstract

Monte-Carlo simulations to calculate the number of prompt particles emitted during fission were performed using the FIFRELIN code and compared to recent experimental data. We show that we are able to reproduce both the neutron and gamma-ray multiplicity distributions as a function of the pre-neutron mass of the fission fragments using a single consistent set of parameters. This result was made possible by using an energy-dependent spin cut-off model, driving the initial total angular momentum of the fission fragments, together with microscopic level densities from the HFB plus combinatorial method. We also discuss, how the initial excitation-energy sharing shapes the TKE-dependent gamma-ray multiplicity.(c) 2022 French Alternative Energies and Atomic Energy Commission (CEA). Published by Elsevier B.V.This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.

Published
2023
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35. New results in the modeling of fission and radiative neutron capture with FIFRELIN

Author

Olivier Litaize, Valentin Piau, Achment Chalil, Tatsuhiko Ogawa, Abdel Chebboubi, Alf Göök, Franck Gunsing, Grégoire Kessedjian, David Lhuillier, Davide Mancusi, Thomas Materna, Andreas Oberstedt, Stephan Oberstedt, Olivier Serot, and Loïc Thulliez

Subjects
General Medicine
Abstract

The FIFRELIN Monte Carlo code has been upgraded recently by adding new capabilities, additional models and updated databases. Several examples are presented in this work as well as three different applications related to the prompt component in fission, gamma cascades from thermal neutron capture and the delayed component in fission associated to the time evolution of decay heat.

Published
2023
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36. 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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37. JRC MONNET – the intense fast-neutron source for fundamental and application-driven research

Author

Cristiano Lino Fontana, Bonaldi Cédric, Wouter Geerts, Miguel Macías Martinez, Marzio Vidali, and Stephan Oberstedt

Subjects
General Medicine
Abstract

MONNET is a fast-neutron source based on a 3.5 MV tandem accelerator, located at the Geel (BE) site of the Joint esearch Centre. It became operational in 2020. MONNET may deliver intense neutron beams in the energy range from 30 keV to 10.1 MeV and from 12.8 MeV to 24 MeV. Neutrons are generated by means of nuclear reactions in the target material (e.g. protons or deuterons on lithium-7, tritium or deuterium targets). MONNET delivers a neutron flux of up to 109 n/sr/s, depending on the producing reaction and the neutron energy. Neutron beams are essentially mono-energetic (∆En/En < 6% with En > 300 keV). The accelerator may also be used with proton and deuteron beams. Alpha beams will be offered soon. Photon beams are possible and presently under investigation. The research program ranges from cross section measurements, e.g. (n, f), (n, p), (n, α) as well as (p, p′), (p, n) and (p, γ), nuclear fission research, material studies (e.g. radiation-induced damage), to the investigation of advanced methods in nuclear technologies, safety and security. The MONNET neutron source offers beamtime to external user within the JRC EUFRAT Open Access program. Proposal evaluation by an independent panel is taking place up to two times per year.

Published
2023
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