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1. Nuclear charge radii of germanium isotopes around $N$ = 40

Author

Wang, S. J., Kanellakopoulos, A., Yang, X. F., Bai, S. W., Billowes, J., Bissell, M. L., Blaum, K., Cheal, B., Devlin, C. S., Ruiz, R. F. Garcia, Han, J. Z., Heylen, H., Kaufmann, S., Konig, K., Koszorus, A., Lechner, S., Malbrunot-Ettenauer, S., Nazarewicz, W., Neugart, R., Neyens, G., Nortershauser, W., Ratajczyk, T., Reinhard, P. -G., Rodrıguez, L. V., Sels, S., Xie, L., Xu, Z. Y., Yordanov, D. T., and Yu, Y. M.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

Collinear laser spectroscopy measurements were performed on $^{68-74}$Ge isotopes ($Z = 32$) at ISOLDE-CERN, by probing the $4s^2 4p^2 \, ^3\!P_1 \rightarrow 4s^2 4p 5s \, ^3\!P_1^o$ atomic transition (269~nm) of germanium. Nuclear charge radii are determined via the measured isotope shifts, revealing a larger local variation than the neighboring isotopic chains. Nuclear density functional theory with the Fayans functionals Fy($\Delta r$,HFB) and Fy(IVP), and the SV-min Skyrme describes the experimental data for the differential charge radii $\delta\langle r^{2} \rangle$ and charge radii $R_{\rm c}$ within the theoretical uncertainties. The observed large variation in the charge radii of germanium isotopes is better accounted for by theoretical models incorporating ground state quadrupole correlations. This suggests that the polarization effects due to pairing and deformation contribute to the observed large odd-even staggering in the charge radii of the Ge isotopic chain., Comment: 6 pages,5 figures

Published
2024
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2. Charge radii, moments and masses of mercury isotopes across the N = 126 shell closure

Author

Goodacre, T. Day, Afanasjev, A. V., Barzakh, A. E., Nies, L., Marsh, B. A., Sels, S., Perera, U. C., Ring, P., Wienholtz, F., Andreyev, A. N., Van Duppen, P., Althubiti, N. A., Andel, B., Atanasov, D., Augusto, R. S., Billowes, J., Blaum, K., Cocolios, T. E., Cubiss, J. G., Farooq-Smith, G. J., Fedorov, D. V., Fedosseev, V. N., Flanagan, K. T., Gaffney, L. P., Ghys, L., Gottberg, A., Huyse, M., Kreim, S., Kunz, P., Lunney, D., Lynch, K. M., Manea, V., Palenzuela, Y. Martinez, Medonca, T. M., Molkanov, P. L., Mougeot, M., Ramos, J. P., Rosenbusch, M., Rossel, R. E., Rothe, S., Schweikhard, L., Seliverstov, M. D., Spagnoletti, P., Van Beveren, C., Veinhard, M., Verstraelen, E., Welker, A., Wendt, K., Wolf, R. N., Zadvornaya, A., and Zuber, K.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

Combining laser spectroscopy in a Versatile Arc Discharge and Laser Ion Source, with Penning-trap mass spectrometry at the CERN-ISOLDE facility, this work reports on mean-square charge radii of neutron-rich mercury isotopes across the $N = 126$ shell closure, the electromagnetic moments of $^{207}$Hg and more precise mass values of $^{206-208}$Hg. The odd-even staggering (OES) of the mean square charge radii and the kink at $N = 126$ are analyzed within the framework of covariant density functional theory (CDFT), with comparisons between different functionals to investigate the dependence of the results on the underlying single-particle structure. The observed features are defined predominantly in the particle-hole channel in CDFT, since both are present in the calculations without pairing. However, the magnitude of the kink is still affected by the occupation of the $1i_{11/2}$ and $2g_{9/2}$ orbitals with a dependence on the relative energies as well as pairing., Comment: 20 pages, 12 figures, Phys. Rev. C in press

Published
2021
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3. Laser spectroscopy of neutron-rich $^{207,208}$Hg isotopes: Illuminating the kink and odd-even staggering in charge radii across the $N=126$ shell closure

Author

Goodacre, T. Day, Afanasjev, A. V., Barzakh, A. E., Marsh, B. A., Sels, S., Ring, P., Nakada, H., Andreyev, A. N., Van Duppen, P., Althubiti, N. A., Andel, B., Atanasov, D., Billowes, J., Blaum, K., Cocolios, T. E., Cubiss, J. G., Farooq-Smith, G. J., Fedorov, D. V., Fedosseev, V. N., Flanagan, K. T., Ganey, L. P., Ghys, L., Huyse, M., Kreim, S., Lunney, D., Lynch, K. M., Manea, V., Palenzuela, Y. Martinez, Molkanov, P. L., Rosenbusch, M., Rossel, R. E., Rothe, S., Schweikhard, L., Seliverstov, M. D., Spagnoletti, P., Van Beveren, C., Veinhard, M., Verstraelen, E., Welker, A., Wendt, K., Wienholtz, F., Wolf, R. N., Zadvornaya, A., and Zuber, K.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

The mean-square charge radii of $^{207,208}$Hg ($Z=80, N=127,128$) have been studied for the first time and those of $^{202,203,206}$Hg ($N=122,123,126$) remeasured by the application of in-source resonance-ionization laser spectroscopy at ISOLDE (CERN). The characteristic \textit{kink} in the charge radii at the $N=126$ neutron shell closure has been revealed, providing the first information on its behavior below the $Z=82$ proton shell closure. A theoretical analysis has been performed within relativistic Hartree-Bogoliubov and non-relativistic Hartree-Fock-Bogoliubov approaches, considering both the new mercury results and existing lead data. Contrary to previous interpretations, it is demonstrated that both the kink at $N=126$ and the odd-even staggering (OES) in its vicinity can be described predominately at the mean-field level, and that pairing does not need to play a crucial role in their origin. A new OES mechanism is suggested, related to the staggering in the occupation of the different neutron orbitals in odd- and even-$A$ nuclei, facilitated by particle-vibration coupling for odd-$A$ nuclei., Comment: 7 pages, 5 figures, Physical Review C, in press

Published
2020
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4. Nuclear Moments of Germanium Isotopes around $N$ = 40

Author

Kanellakopoulos, A., Yang, X. F., Bissell, M. L., Reitsma, M. L., Bai, S. W., Billowes, J., Blaum, K., Borschevsky, A., Cheal, B., Devlin, C. S., Ruiz, R. F. Garcia, Heylen, H., Kaufmann, S., König, K., Koszorús, Á., Lechner, S., Malbrunot-Ettenauer, S., Neugart, R., Neyens, G., Nörtershäuser, W., Ratajczyk, T., Rodríguez, L. V., Sels, S., Wang, S. J., Xie, L., Xu, Z. Y., and Yordanov, D. T.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

Collinear laser spectroscopy measurements were performed on $^{69,71,73}$Ge isotopes ($Z = 32$) at ISOLDE-CERN. The hyperfine structure of the $4s^2 4p^2 \, ^3P_1 \rightarrow 4s^2 4p 5s \, ^3P_1^o$ transition of the germanium atom was probed with laser light of 269 nm, produced by combining the frequency-mixing and frequency-doubling techniques. The hyperfine fields for both atomic levels were calculated using state-of-the-art atomic relativistic Fock-space coupled-cluster calculations. A new $^{73}$Ge quadrupole moment was determined from these calculations and previously measured precision hyperfine parameters, yielding $Q_{\rm s}$ = $-$0.198(4) b, in excellent agreement with the literature value from molecular calculations. The moments of $^{69}$Ge have been revised: $\mu$ = +0.920(5) $\mu_{N}$ and $Q_{\rm s}$= +0.114(8) b, and those of $^{71}$Ge have been confirmed. The experimental moments around $N = 40$ are interpreted with large-scale shell-model calculations using the JUN45 interaction, revealing rather mixed wave function configurations, although their $g$-factors are lying close to the effective single-particle values. Through a comparison with neighboring isotones, the structural change from the single-particle nature of nickel to deformation in germanium is further investigated around $N = 40$., Comment: accepted in Phys. Rev. C., in production

Published
2020
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5. Shape staggering of mid-shell mercury isotopes from in-source laser spectroscopy compared with Density Functional Theory and Monte Carlo Shell Model calculations

Author

Sels, S., Goodacre, T. Day, Marsh, B. A., Pastore, A., Ryssens, W., Tsunoda, Y., Althubiti, N., Andel, B., Andreyev, A. N., Atanasov, D., Barzakh, A. E., Bender, M., Billowes, J., Blaum, K., Cocolios, T. E., Cubiss, J. G., Dobaczewski, J., Farooq-Smith, G. J., Fedorov, D. V., Fedosseev, V. N., Flanagan, K. T., Gaffney, L. P., Ghys, L., Heenen, P-H., Huyse, M., Kreim, S., Lunney, D., Lynch, K. M., Manea, V., Palenzuela, Y. Martinez, Medonca, T. M., Molkanov, P. L., Otsuka, T., Ramos, J. P., Rossel, R. E., Rothe, S., Schweikhard, L., Seliverstov, M. D., Spagnoletti, P., Van Beveren, C., Van Duppen, P., Veinhard, M., Verstraelen, E., Welker, A., Wendt, K., Wienholtz, F., Wolf, R. N., and Zadvornaya, A.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

Neutron-deficient $^{177-185}$Hg isotopes were studied using in-source laser resonance-ionization spectroscopy at the CERN-ISOLDE radioactive ion-beam facility, in an experiment combining different detection methods tailored to the studied isotopes. These include either alpha-decay tagging or Multi-reflection Time-of-Flight gating to identify the isotopes of interest. The endpoint of the odd-even nuclear shape staggering in mercury was observed directly by measuring for the first time the isotope shifts and hyperfine structures of $^{177-180}$Hg. Changes in the mean-square charge radii for all mentioned isotopes, magnetic dipole and electric quadrupole moments of the odd-A isotopes and arguments in favor of $I = 7/2$ spin assignment for $^{177,179}$Hg were deduced. Experimental results are compared with Density Functional Theory (DFT) and Monte-Carlo Shell Model (MCSM) calculations. DFT calculations with several Skyrme parameterizations predict a large jump in the charge radius around the neutron $N = 104$ mid shell, with an odd-even staggering pattern related to the coexistence of nearly-degenerate oblate and prolate minima. This near-degeneracy is highly sensitive to many aspects of the effective interaction, a fact that renders perfect agreement with experiment out of reach for current functionals. Despite this inherent diffculty, the SLy5s1 and a modified UNEDF1^{SO} parameterization predict a qualitatively correct staggering that is off by two neutron numbers. MCSM calculations of states with the experimental spins and parities show good agreement for both electromagnetic moments and the observed charge radii. A clear mechanism for the origin of shape staggering within this context is identified: a substantial change in occupancy of the proton $\pi h_{9/2}$ and neutron $\nu i_{13/2}$ orbitals., Comment: 19 pages, 18 figures

Published
2019
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6. PUMA, antiProton unstable matter annihilation

Author

Aumann, T., Bartmann, W., Boine-Frankenheim, O., Bouvard, A., Broche, A., Butin, F., Calvet, D., Carbonell, J., Chiggiato, P., de Gersem, H., de Oliveira, R., Dobers, T., Ehm, F., Somoza, J.Ferreira, Fischer, J., Fraser, M., Friedrich, E., Frotscher, A., Gomez-Ramos, M., Grenard, J.L., Hobl, A., Hupin, G., Husson, A., Indelicato, P., Johnston, K., Klink, C., Kubota, Y., Lazauskas, R., Malbrunot-Ettenauer, S., Marsic, N., O Müller, W.F., Naimi, S., Nakatsuka, N., Necca, R., Neidherr, D., Neyens, G., Obertelli, A., Ono, Y., Pasinelli, S., Paul, N., Pollacco, E.C., Rossi, D., Scheit, H., Schlaich, M., Schmidt, A., Schweikhard, L., Seki, R., Sels, S., Siesling, E., Uesaka, T., Vilén, M., Wada, M., Wienholtz, F., Wycech, S., Zacarias, S., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire Kastler Brossel (LKB [Collège de France]), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and PUMA

Subjects
CERN Lab, experimental methods, Nuclear Theory, p: density, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], sensitivity, annihilation, nuclear physics, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Physics - Experiment, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Physics::Atomic Physics, nucleus: density, Detectors and Experimental Techniques, nucleus: surface, Nuclear Experiment, activity report
Abstract

International audience; PUMA, antiProton Unstable Matter Annihilation, is a nuclear-physics experiment at CERN aiming at probing the surface properties of stable and rare isotopes by use of low-energy antiprotons. Low-energy antiprotons offer a very unique sensitivity to the neutron and proton densities at the annihilation site, i.e. in the tail of the nuclear density. Today, no facility provides a collider of low-energy radioactive ions and low-energy antiprotons: while not being a collider experiment, PUMA aims at transporting one billion antiprotons from ELENA, the Extra-Low-ENergy Antiproton ring, to ISOLDE, the rare-isotope beam facility of CERN. PUMA will enable the capture of low-energy antiprotons by short-lived nuclei and the measurement of the emitted radiations. In this way, PUMA will give access to the so-far largely unexplored isospin composition of the nuclear-radial-density tail of radioactive nuclei. The motivations, concept and current status of the PUMA experiment are presented.

Published
2022

7. Laser Spectroscopy of Neutron-Rich $^{207,208}$Hg Isotopes: Illuminating the Kink and Odd-Even Staggering in Charge Radii across the $N=126$ Shell Closure

Author

Day Goodacre, T., Afanasjev, A. V., Barzakh, A. E., Marsh, B. A., Sels, S., Ring, P., Nakada, H., Andreyev, A. N., Van Duppen, P., Althubiti, N. A., Andel, B., Atanasov, D., Billowes, J., Blaum, K., Cocolios, T. E., Cubiss, J. G., Farooq-Smith, G. J., Fedorov, D. V., Fedosseev, V. N., Flanagan, K. T., Gaffney, L. P., Ghys, L., Huyse, M., Kreim, S., Lunney, D., Lynch, K. M., Manea, V., Martinez Palenzuela, Y., Molkanov, P. L., Rosenbusch, M., Rossel, R. E., Rothe, S., Schweikhard, L., Seliverstov, M. D., Spagnoletti, P., Van Beveren, C., Veinhard, M., Verstraelen, E., Welker, A., Wendt, K., Wienholtz, F., Wolf, R. N., Zadvornaya, A., Zuber, K., Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear Theory, nucl-th, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucl-ex, Nuclear Theory (nucl-th), Nuclear Physics - Theory, Nuclear Physics - Experiment, Nuclear Experiment (nucl-ex), Präzisionsexperimente - Abteilung Blaum, Nuclear Experiment, Nuclear Physics
Abstract

The mean-square charge radii of $^{207,208}$Hg ($Z=80, N=127,128$) have been studied for the first time and those of $^{202,203,206}$Hg ($N=122,123,126$) remeasured by the application of in-source resonance-ionization laser spectroscopy at ISOLDE (CERN). The characteristic \textit{kink} in the charge radii at the $N=126$ neutron shell closure has been revealed, providing the first information on its behavior below the $Z=82$ proton shell closure. A theoretical analysis has been performed within relativistic Hartree-Bogoliubov and non-relativistic Hartree-Fock-Bogoliubov approaches, considering both the new mercury results and existing lead data. Contrary to previous interpretations, it is demonstrated that both the kink at $N=126$ and the odd-even staggering (OES) in its vicinity can be described predominately at the mean-field level, and that pairing does not need to play a crucial role in their origin. A new OES mechanism is suggested, related to the staggering in the occupation of the different neutron orbitals in odd- and even-$A$ nuclei, facilitated by particle-vibration coupling for odd-$A$ nuclei., Comment: 7 pages, 5 figures, Physical Review C, in press

Published
2021

8. Laser-assisted nuclear decay spectroscopy of $^{176,177,179}$Au

Author

Harding, R. D., Andreyev, A. N., Barzakh, A. E., Cubiss, J. G., Van Duppen, P., Al Monthery, M., Althubiti, N. A., Andel, B., Antalic, S., Cocolios, T. E., Goodacre, T. Day, Dockx, K., Farooq-Smith, G. J., Fedorov, D. V., Fedosseev, V. N., Fink, D. A., Gaffney, L. P., Ghys, L., Johnson, J. D., Joss, D. T., Huyse, M., Imai, N., Lynch, K. M., Marsh, B. A., Martinez Palenzuela, Y., Molkanov, P. L., O'Neill, G. G., Page, R. D., Rossel, R. E., Rothe, S., Seliverstov, M. D., Sels, S., Van Beveren, C., and Verstraelen, E.

Subjects
Nuclear Physics - Experiment, Physics::Atomic Physics, Nuclear Experiment
Abstract

A study of the laser-ionized and mass-separated neutron-deficient isotopes $^{176,177,179}$Au was performed using the Resonance Ionization Laser Ion Source and the Windmill detection setup at ISOLDE, CERN. New and improved data on complex fine-structure α decays of the three isotopes were deduced, providing insight into the low-lying levels in the daughter nuclei $^{172,173,175}$Ir. New information on the properties of β-decay daughter products $^{177,179}$Pt was also obtained. From the first in-source laser spectroscopy measurements of the hyperfine structure in the atomic 267.6-nm transition of 176Au, the nuclear magnetic moments for both high- and low-spin α-decaying states were deduced. Together with the values determined from the additivity relations, they were used to propose the most probable spins and configurations for both states. The α-decay branching ratios were determined as $b_{\alpha}$ $\left (^{176}\textrm{Au}^{ls}\right)=58(5)$% and $b_{\alpha}$ $(^{176} \textrm{Au}^{hs})=29(5)$%.

Published
2021

9. $β$ -delayed fission of isomers in $^{188}$Bi

Author

Andel, B, Andreyev, A N, Antalic, S, Al Monthery, M, Barzakh, A, Bissell, M L, Chrysalidis, K, Cocolios, T E, Cubiss, J G, Day Goodacre, T, Dubray, N, Farooq-Smith, G J, Fedorov, D V, Fedosseev, V N, Gaffney, L P, Garcia Ruiz, R F, Goriely, S, Granados, C, Harding, R D, Heinke, R, Hilaire, S, Huyse, M, Lemaître, J F, Lynch, K M, Marsh, B A, Molkanov, P, Mosat, P, Péru, S, Raison, C, Rothe, S, Seiffert, C, Seliverstov, M D, Sels, S, Studer, D, Sundberg, J, Van Duppen, P, Direction des Applications Militaires (DAM), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

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

International audience; $β$-delayed fission ($β$DF) decay of a low-spin (ls) and a high-spin (hs) isomer in $^{188}$Bi was studied at the ISOLDE facility at CERN. Isomer-selective laser ionization and time gating were employed to investigate each isomer separately and their $β$DF partial half-lives were determined: $T_{1/2\mathrm{p},β\mathrm{DF}} (^{188}\mathrm{Bi^{ls}})=5.6(8)×10^3$ s and $T_{1/2\mathrm{p},β\mathrm{DF}} (^{188}\mathrm{Bi^{hs}})=1.7(6)×10^3$ s. This work is the first βDF study of two states in one isotope and allows the spin dependence of low-energy fission to be explored. The fission fragment mass distribution of a daughter nuclide $^{188}$Pb, following the $β$ decay of the high-spin isomer, was deduced and indicates a mixture of symmetric and asymmetric fission modes. Experimental results were compared with self-consistent mean-field calculations based on the finite-range Gogny D1M interaction. To reproduce the measured $T_{1/2\mathrm{p},β\mathrm{DF}} (^{188}\mathrm{Bi^{hs}})$, the calculated fission barrier of $^{188}$Pb had to be reduced by ≈30%. After this reduction, the measured $T_{1/2\mathrm{p},β\mathrm{DF}} (^{188}\mathrm{Bi^{ls}})$ was in agreement with calculations for a few possible configurations for $^{188}\mathrm{Bi^{ls}}$. Theoretical $β$DF probabilities for these configurations were found to be lower by a factor of 4–9 than the $β$DF probability of $^{188}\mathrm{Bi^{hs}}$. The fission fragment mass distribution of $^{188}$Pb was compared to the scission-point model SPY and the calculations based on the finite-range liquid-drop model. The first observation of $β$DF for $^{190}$Bi is also reported.

Published
2020

10. Laser-assisted decay spectroscopy and mass spectrometry of $^{178}\mathrm{Au}$

Author

Cubiss, J.G., Andreyev, A.N., Barzakh, A.E., Manea, V., Al Monthery, M., Althubiti, N.A., Andel, B., Antalic, S., Atanasov, D., Blaum, K., Cocolios, T.E., Day Goodacre, T., De Roubin, A., Farooq-Smith, G.J., Fedorov, D.V., Fedosseev, V.N., Fink, D.A., Gaffney, L.P., Ghys, L., Harding, R.D., Herfurth, F., Huyse, M., Imai, N., Joss, D.T., Kreim, S., Lunney, D., Lynch, K.M., Marsh, B.A., Martinez Palenzuela, Y., Molkanov, P.L., Neidherr, D., O'Neill, G.G., Page, R.D., Rosenbusch, M., Rossel, R.E., Rothe, S., Schweikhard, L., Seliverstov, M.D., Sels, S., Stott, A., Van Beveren, C., Van Duppen, P., Verstraelen, E., Welker, A., Wienholtz, F., Wolf, R.N., Zuber, K., Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
[PHYS]Physics [physics], Nuclear Experiment
Abstract

International audience; A comprehensive study of the isotope $^{178}$Auhas been made at the CERN-ISOLDE facility, using resonance laser ionization. Two long-lived states in$^{178}$Auwere identified—a low-spin ground state and a high-spin isomer—each of which were produced as pure beams. Using the ISOLTRAP precision Penning trap, the excitation energy of the isomeric state in$^{178}$Auwas determined to be$E$$^{*}$=189(14)keV. Theα-decay fine structure patterns of the two states were studied using the Windmill decay station, providing information on the low-lying states in the daughter nucleus$^{174}$Ir. Nuclear spin assignments of$I$($^{178}$Au$^{g}$)=(2,3)and$I$($^{178}$Aum)=(7,8)are made based on the observed$\beta$-decay feeding and hyperfine structure intensity patterns. These spin assignments are used for fitting the hyperfine structures of the two states from which values for the magnetic dipole moments are extracted. The extracted moments are compared with calculations using additivity relations to establish the most probable configurations for$^{178}$Au$^{g,m}$.

Published
2020

11. PUMA: antiprotons and radioactive nuclei

Author

Aumann, T, Bartmann, W, Bouvard, A, Boine-Frankenheim, O, Broche, A, Butin, F, Calvet, D, Carbonell, J, Chiggiato, P, De Gersem, H, De Oliveira, R, Dobers, T, Ehm, F, Ferreira Somoza, J, Fischer, J, Fraser, M, Friedrich, E, Grenard, J-L, Hupin, G, Johnston, K, Kubota, Y, Gomez-Ramos, M, Indelicato, P, Lazauskas, R, Malbrunot-Ettenauer, S, Marsic, N, Müller, W, Naimi, S, Nakatsuka, N, Necca, R, Neyens, G, Obertelli, A, Ono, Y, Pasinelli, S, Paul, N, Pollacco, E C, Rossi, D, Scheit, H, Seki, R, Schmidt, A, Schweikhard, L, Sels, S, Siesling, E, Uesaka, T, Wada, M, Wienholtz, F, Wycech, S, and Zacarias, S

Subjects
Nuclear Theory, Physics::Accelerator Physics, High Energy Physics::Experiment, Physics::Atomic Physics, Detectors and Experimental Techniques, Nuclear Experiment
Abstract

Antiprotons as a probe to study short-lived isotopes remain unexploited despite past pioneering works with stable nuclei. In particular, low-energy antiprotons offer a very unique sensitivity to the neutron and proton densities at the annihilation site, i.e. in the tail of the nuclear density. Such studies with short-lived nuclei and low-energy antiprotons are the first motivation of the proposed antiProton Unstable Matter Annihilation (PUMA) experiment. Today, no facility provides a collider of low-energy radioactive ions and low-energy antiprotons: PUMA aims at transporting one billion antiprotons from CERN/ELENA to CERN/ISOLDE to perform the capture of low-energy antiprotons by short-lived nuclei, and probe in this way the so-far unexplored isospin composition of the nuclear-radial-density tail of radioactive nuclei.

Published
2019

12. Inverse odd-even staggering in nuclear charge radii and possible octupole collectivity in 217,218,219At revealed by in-source laser spectroscopy

Author

Barzakh, A. E., Cubiss, J. G., Andreyev, A. N., Seliverstov, M. D., Andel, B., Antalic, S., Ascher, P., Atanasov, D., Beck, D., Bieroifmmode nelse, J., Blaum, K., Borgmann, Ch., Breitenfeldt, M., Capponi, L., Cocolios, T. E., Day Goodacre, T., Derkx, X., De Witte, H., Elseviers, J., Fedorov, D. V., Fedosseev, V. N., Fritzsche, S., Gaffney, L. P., George, S., Ghys, L., Heßberger, F. P., Huyse, M., Imai, N., Kalaninová, Z., Kisler, D., Köster, U., Kowalska, M., Kreim, S., Lane, J. F. W., Liberati, V., Lunney, D., Lynch, K. M., Manea, V., Marsh, B. A., Mitsuoka, S., Molkanov, P. L., Nagame, Y., Neidherr, D., Nishio, K., Ota, S., Pauwels, D., Popescu, L., Radulov, D., Rapisarda, E., Revill, J. P., Rosenbusch, M., Rossel, R. E., Rothe, S., Sandhu, K., Schweikhard, L., Sels, S., Truesdale, V. L., Van Beveren, C., Van den Bergh, P., Van Duppen, P., Wakabayashi, Y., Wendt, K. D. A., Wienholtz, F., Whitmore, B. W., Wilson, G. L., Wolf, R. N., and Zuber, K.

Subjects
Physics::Atomic Physics, Präzisionsexperimente - Abteilung Blaum, Nuclear Experiment
Abstract

© 2019 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Hyperfine-structure parameters and isotope shifts for the 795-nm atomic transitions in At217,218,219 have been measured at CERN-ISOLDE, using the in-source resonance-ionization spectroscopy technique. Magnetic dipole and electric quadrupole moments, and changes in the nuclear mean-square charge radii, have been deduced. A large inverse odd-even staggering in radii, which may be associated with the presence of octupole collectivity, has been observed. Namely, the radius of the odd-odd isotope At218 has been found to be larger than the average of its even-N neighbors, At217,219. The discrepancy between the additivity-rule prediction and experimental data for the magnetic moment of At218 also supports the possible presence of octupole collectivity in the considered nuclei. ispartof: Physical Review C vol:99 issue:5 status: published

Published
2019

13. Inverse odd-even staggering in nuclear charge radii and possible octupole collectivity in $^{217,218,219}\mathrm{At}$ revealed by in-source laser spectroscopy

Author

Barzakh, A.E., Cubiss, J.G., Andreyev, A.N., Seliverstov, M.D., Andel, B., Antalic, S., Ascher, P., Atanasov, D., Beck, D., Bieroń, J., Blaum, K., Borgmann, Ch., Breitenfeldt, M., Capponi, L., Cocolios, T.E., Day Goodacre, T., Derkx, X., De Witte, H., Elseviers, J., Fedorov, D.V., Fedosseev, V.N., Fritzsche, S., Gaffney, L.P., George, S., Ghys, L., Heßberger, F.P., Huyse, M., Imai, N., Kalaninová, Z., Kisler, D., Köster, U., Kowalska, M., Kreim, S., Lane, J.F.W., Liberati, V., Lunney, D., Lynch, K.M., Manea, V., Marsh, B.A., Mitsuoka, S., Molkanov, P.L., Nagame, Y., Neidherr, D., Nishio, K., Ota, S., Pauwels, D., Popescu, L., Radulov, D., Rapisarda, E., Revill, J.P., Rosenbusch, M., Rossel, R.E., Rothe, S., Sandhu, K., Schweikhard, L., Sels, S., Truesdale, V.L., Van Beveren, C., Van Den Bergh, P., Van Duppen, P., Wakabayashi, Y., Wendt, K.D.A., Wienholtz, F., Whitmore, B.W., Wilson, G.L., Wolf, R.N., Zuber, K., Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

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

International audience; Hyperfine-structure parameters and isotope shifts for the 795-nm atomic transitions in $^{217,218,219}$At have been measured at CERN-ISOLDE, using the in-source resonance-ionization spectroscopy technique. Magnetic dipole and electric quadrupole moments, and changes in the nuclear mean-square charge radii, have been deduced. A large inverse odd-even staggering in radii, which may be associated with the presence of octupole collectivity, has been observed. Namely, the radius of the odd-odd isotope $^{218}$At has been found to be larger than the average of its even-$N$ neighbors, $^{217,219}$At. The discrepancy between the additivity-rule prediction and experimental data for the magnetic moment of $^{218}$At also supports the possible presence of octupole collectivity in the considered nuclei.

Published
2019

14. Charge radii and electromagnetic moments of $^{195--211}\mathrm{At}$

Author

Cubiss, JG, Barzakh, AE, Seliverstov, MD, Andreyev, AN, Andel, B, Antalic, S, Ascher, P, Atanasov, D, Beck, D, Bieroń, J, Blaum, K, Borgmann, C, Breitenfeldt, M, Capponi, L, Cocolios, TE, Day Goodacre, T, Derkx, X, De Witte, H, Elseviers, J, Fedorov, DV, Fedosseev, VN, Fritzsche, S, Gaffney, LP, George, S, Ghys, L, Heßberger, FP, Huyse, M, Imai, N, Kalaninová, Z, Kisler, D, Köster, U, Kowalska, M, Kreim, S, Lane, JFW, Liberati, V, Lunney, D, Lynch, KM, Manea, V, Marsh, BA, Mitsuoka, S, Molkanov, PL, Nagame, Y, Neidherr, D, Nishio, K, Ota, S, Pauwels, D, Popescu, L, Radulov, D, Rapisarda, E, Revill, JP, Rosenbusch, M, Rossel, RE, Rothe, S, Sandhu, K, Schweikhard, L, Sels, S, Truesdale, VL, Van Beveren, C, Van den Bergh, P, Wakabayashi, Y, Van Duppen, P, Wendt, KDA, Wienholtz, F, Whitmore, BW, Wilson, GL, Wolf, RN, and Zuber, K

Subjects
Nuclear Experiment
Abstract

© 2018 authors. Hyperfine-structure parameters and isotope shifts of At195-211 have been measured for the first time at CERN-ISOLDE, using the in-source resonance-ionization spectroscopy method. The hyperfine structures of isotopes were recorded using a triad of experimental techniques for monitoring the photo-ion current. The Multi-Reflection Time-of-Flight Mass Spectrometer, in connection with a high-resolution electron multiplier, was used as an ion-counting setup for isotopes that either were affected by strong isobaric contamination or possessed a long half-life; the ISOLDE Faraday cups were used for cases with high-intensity beams; and the Windmill decay station was used for short-lived, predominantly α-decaying nuclei. The electromagnetic moments and changes in the mean-square charge radii of the astatine nuclei have been extracted from the measured hyperfine-structure constants and isotope shifts. This was only made possible by dedicated state-of-the-art large-scale atomic computations of the electronic factors and the specific mass shift of atomic transitions in astatine that are needed for these extractions. By comparison with systematics, it was possible to assess the reliability of the results of these calculations and their ascribed uncertainties. A strong deviation in the ground-state mean-square charge radii of the lightest astatine isotopes, from the trend of the (spherical) lead isotopes, is interpreted as the result of an onset of deformation. This behavior bears a resemblance to the deviation observed in the isotonic polonium isotopes. Cases for shape coexistence have been identified in At197,199, for which a significant difference in the charge radii for ground (9/2-) and isomeric (1/2+) states has been observed. ispartof: Physical Review C vol:97 issue:5 status: Published online

Published
2018

15. Charge radii and electromagnetic moments of $^{195 – 211}$At

Author

Cubiss, J. G., Barzakh, A. E., Seliverstov, M. D., Andreyev, A. N., Andel, B., Antalic, S., Ascher, P., Atanasov, D., Beck, D., Bieroń, J., Blaum, K., Borgmann, Ch., Breitenfeldt, M., Capponi, L, Cocolios, T. E., Day Goodacre, T., Derkx, X., De Witte, H., Elseviers, J., Fedorov, D. V., Fedosseev, V N, Fritzsche, S., Gaffney, L. P., George, S., Ghys, L., Heßberger, F. P., Huyse, M., Imai, N., Kalaninová, Z., Kisler, D., Köster, U., Kowalska, M., Kreim, S., Lane, J. F. W., Liberati, V., Lunney, D., Lynch, K. M., Manea, V., Marsh, B. A., Mitsuoka, S., Molkanov, P. L., Nagame, Y., Neidherr, D., Nishio, K., Ota, S., Pauwels, D., Popescu, L., Radulov, D., Rapisarda, E., Revill, J. P., Rosenbusch, M., Rossel, R.E., Rothe, S., Sandhu, K., Schweikhard, L., Sels, S., Truesdale, V. L., Van Beveren, C., Van den Bergh, P., Wakabayashi, Y., Van Duppen, P., Wendt, K.D.A., Wienholtz, F., Whitmore, B. W., Wilson, G. L., Wolf, R.N., Zuber, K, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Laue-Langevin (ILL), ILL, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
ddc:530, Physics::Atomic Physics, Präzisionsexperimente - Abteilung Blaum, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

Physical review / C 97(5), 054327 (2018). doi:10.1103/PhysRevC.97.054327, Published by Inst., Woodbury, NY

Published
2018

16. β -delayed fission and α decay of at 196

Author

Truesdale, V. L., Andreyev, A. N., Ghys, L., Huyse, M., Van Duppen, P., Sels, S., Andel, B., Antalic, S., Barzakh, A., Capponi, L., Cocolios, T. E., Derkx, X., De Witte, H., Elseviers, J., Fedorov, D. V., Fedosseev, V. N., Heßberger, F. P., Kalaninová, Z., Köster, U., Lane, J. F W, Liberati, V., Lynch, K. M., Marsh, B. A., Mitsuoka, S., Nagame, Y., Nishio, K., Ota, S., Pauwels, D., Popescu, L., Radulov, D., Rapisarda, E., Rothe, S., Sandhu, K., Seliverstov, M. D., Sjödin, A. M., Van Beveren, C., Van Den Bergh, P., and Wakabayashi, Y.

Subjects
Nuclear Experiment
Abstract

A nuclear-decay spectroscopy study of the neutron-deficient isotope At196 is reported where an isotopically pure beam was produced using the selective Resonance Ionization Laser Ion Source and On-Line Isotope Mass Separator (CERN). The fine-structure α decay of At196 allowed the low-energy excited states in the daughter nucleus Bi192 to be investigated. A β-delayed fission study of At196 was also performed. A mixture of symmetric and asymmetric fission-fragment mass distributions of the daughter isotope Po196 (populated by β decay of At196) was deduced based on the measured fission-fragment energies. A βDF probability PβDF(At196)=9(1)×10-5 was determined.

Published
2016

17. β-delayed fission and α decay of 196At

Author

Truesdale, V. L., Andreyev, A. N., Ghys, L., Huyse, M., Van Duppen, P., Sels, S., Andel, B., Antalic, S., Barzakh, A., Capponi, L., Cocolios, T. E., Derkx, X., De Witte, H., Elseviers, J., Fedorov, D. V., Fedosseev, V. N., Hessberger, Fritz-Peter, Kalaninová, Z., Köster, U., Lane, J. F. W., Liberati, V., Lynch, K. M., Marsh, B. A., Mitsuoka, S., Nagame, Y., Nishio, K., Ota, S., Pauwels, D., Popescu, L., Radulov, D., Rapisarda, E., Rothe, S., Sandhu, K., Seliverstov, M. D., Sjödin, A. M., Van Beveren, C., Van Den Bergh, P., and Wakabayashi, Y.

Subjects
ddc:530, Nuclear Experiment
Abstract

Physical review / C covering nuclear physics 94(3), 034308(2016). doi:10.1103/PhysRevC.94.034308, Published by Inst., Woodbury, NY

Published
2016

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