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1. High-spin states in 212Po above the α-decaying (18+) isomer

Author

L. Zago, A. Gottardo, J.J. Valiente-Dobón, G. Benzoni, A. Gadea, M. Górska, S. Lunardi, Zs. Podolyák, P.H. Regan, D. Rudolph, A. Algora, G. de Angelis, D. Bazzacco, J. Benlliure, P. Boutachkov, A. Bracco, A.M. Bruce, F. Camera, E. Casarejos, M.L. Cortés, F.C.L. Crespi, A. Corsi, C. Domingo-Pardo, M. Doncel, T. Engert, H. Geissel, J. Gerl, A. Goasduff, N. Goel, J. Grebosz, E. Gregor, T. Habermann, S. Klupp, I. Kojouharov, N. Kurz, S.M. Lenzi, S. Leoni, S. Mandal, R. Menegazzo, D. Mengoni, B. Million, A.I. Morales, D.R. Napoli, F. Naqvi, C. Nociforo, M. Pfützner, S. Pietri, A. Prochazka, F. Recchia, E. Sahin, H. Schaffner, A. Sharma, B. Sitar, D. Siwal, P. Strmen, I. Szarka, C.A. Ur, P.M. Walker, H. Weick, O. Wieland, and H.-J. Wollersheim

Subjects
γ spectroscopy, Isomer spectroscopy, High-spin spectroscopy, Physics, QC1-999
Abstract

The nucleus 212Po has been produced through the fragmentation of a 238U primary beam at 1 GeV/nucleon at GSI, separated with the FRagment Separator, FRS, and studied via isomer γ-decay spectroscopy with the RISING setup. Two delayed previously unknown γ rays have been observed. One has been attributed to the E3 decay of a 21− isomeric state feeding the α-emitting 45-s (18+) high-spin isomer. The other γ-ray line has been assigned to the decay of a higher-lying 23+ metastable state. These are the first observations of high-spin states above the 212Po (18+) isomer, by virtue of the selectivity obtained via ion-by-ion identification of 238U fragmentation products. Comparison with shell-model calculations points to shortfalls in the nuclear interactions involving high-j proton and neutron orbitals, to which the region around Z∼100 is sensitive.

Published
2022
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2. Unveiling the two-proton halo character of 17Ne: Exclusive measurement of quasi-free proton-knockout reactions

Author

C. Lehr, F. Wamers, F. Aksouh, Yu. Aksyutina, H. Álvarez-Pol, L. Atar, T. Aumann, S. Beceiro-Novo, C.A. Bertulani, K. Boretzky, M.J.G. Borge, C. Caesar, M. Chartier, A. Chatillon, L.V. Chulkov, D. Cortina-Gil, P. Díaz Fernández, H. Emling, O. Ershova, L.M. Fraile, H.O.U. Fynbo, D. Galaviz, H. Geissel, M. Heil, M. Heine, D.H.H. Hoffmann, M. Holl, H.T. Johansson, B. Jonson, C. Karagiannis, O.A. Kiselev, J.V. Kratz, R. Kulessa, N. Kurz, C. Langer, M. Lantz, T. Le Bleis, R. Lemmon, Yu.A. Litvinov, B. Löher, K. Mahata, J. Marganiec-Galązka, C. Müntz, T. Nilsson, C. Nociforo, W. Ott, V. Panin, S. Paschalis, A. Perea, R. Plag, R. Reifarth, A. Richter, K. Riisager, C. Rodriguez-Tajes, D. Rossi, D. Savran, H. Scheit, G. Schrieder, P. Schrock, H. Simon, J. Stroth, K. Sümmerer, O. Tengblad, H. Weick, and C. Wimmer

Subjects
Physics, QC1-999
Abstract

The proton drip-line nucleus 17Ne is investigated experimentally in order to determine its two-proton halo character. A fully exclusive measurement of the 17Ne(p,2p)16F→15⁎O+p quasi-free one-proton knockout reaction has been performed at GSI at around 500 MeV/nucleon beam energy. All particles resulting from the scattering process have been detected. The relevant reconstructed quantities are the angles of the two protons scattered in quasi-elastic kinematics, the decay of 16F into 15O (including γ decays from excited states) and a proton, as well as the 15O+p relative-energy spectrum and the 16F momentum distributions. The latter two quantities allow an independent and consistent determination of the fractions of l=0 and l=2 motion of the valence protons in 17Ne. With a resulting relatively small l=0 component of only around 35(3)%, it is concluded that 17Ne exhibits a rather modest halo character only. The quantitative agreement of the two values deduced from the energy spectrum and the momentum distributions supports the theoretical treatment of the calculation of momentum distributions after quasi-free knockout reactions at high energies by taking into account distortions based on the Glauber theory. Moreover, the experimental data allow the separation of valence-proton knockout and knockout from the 15O core. The latter process contributes with 11.8(3.1) mb around 40% to the total proton-knockout cross section of 30.3(2.3) mb, which explains previously reported contradicting conclusions derived from inclusive cross sections.

Published
2022
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3. The (6+) isomer in 102Sn revisited: Neutron and proton effective charges close to the double shell closure

Author

H. Grawe, K. Straub, T. Faestermann, M. Górska, C. Hinke, R. Krücken, F. Nowacki, M. Böhmer, P. Boutachkov, H. Geissel, R. Gernhäuser, A. Gottardo, J. Grȩbosz, N. Kurz, Z. Liu, L. Maier, S. Pietri, Zs. Podolyák, K. Steiger, H. Weick, H.J. Wollersheim, P.J. Woods, N. Al-Dahan, N. Alkhomashi, A. Ataç, A. Blazhev, N. Braun, I. Čeliković, T. Davinson, I. Dillmann, C. Domingo-Pardo, P. Doornenbal, G. Farrelly, F. Farinon, G. de France, J. Gerl, N. Goel, T. Habermann, R. Hoischen, R. Janik, M. Karny, A. Kaşkaş, I. Kojouharov, Th. Kröll, M. Lewitowicz, Yu.A. Litvinov, S. Myalski, F. Nebel, S. Nishimura, C. Nociforo, J. Nyberg, A. Parikh, A. Procházka, P.H. Regan, C. Rigollet, H. Schaffner, C. Scheidenberger, S. Schwertel, P.-A. Söderström, S. Steer, A. Stolz, and P. Strmeň

Subjects
Electromagnetic transitions, Shell model, Effective charges near 100Sn, Physics, QC1-999
Abstract

In a high-energy fragmentation experiment at GSI an I=π(6+) isomer and its γ-decay are identified in 102Sn, the two-neutron neighbour of the doubly-magic 100Sn. Its half-life is measured to be T=1/2367(11) ns. The possible existence of further isomers is discussed in the framework of large-scale shell model (LSSM) calculations including up to five particle-hole excitations of the 100Sn core. From the precise B(E2; 6+→4+) strength and the recently remeasured value for B(E2; 8+→6+) in the two-proton hole neighbour 98Cd effective E2 polarization charges for protons and neutrons were inferred including LSSM corrections within the full N=4 0ħω space. The results are discussed in comparison to predicted and empirically determined effective operators.

Published
2021
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4. Quasi-free neutron and proton knockout reactions from light nuclei in a wide neutron-to-proton asymmetry range

Author

M. Holl, V. Panin, H. Alvarez-Pol, L. Atar, T. Aumann, S. Beceiro-Novo, J. Benlliure, C.A. Bertulani, J.M. Boillos, K. Boretzky, M. Caamaño, C. Caesar, E. Casarejos, W. Catford, J. Cederkall, L. Chulkov, D. Cortina-Gil, E. Cravo, I. Dillmann, P. Díaz Fernández, Z. Elekes, J. Enders, L.M. Fraile, D. Galaviz Redondo, R. Gernhäuser, P. Golubev, T. Heftrich, M. Heil, M. Heine, A. Heinz, A. Henriques, H.T. Johansson, B. Jonson, N. Kalantar-Nayestanaki, R. Kanungo, A. Kelic-Heil, T. Kröll, N. Kurz, C. Langer, T. Le Bleis, S. Lindberg, J. Machado, E. Nacher, M.A. Najafi, T. Nilsson, C. Nociforo, S. Paschalis, M. Petri, R. Reifarth, G. Ribeiro, C. Rigollet, D.M. Rossi, D. Savran, H. Scheit, H. Simon, O. Sorlin, I. Syndikus, O. Tengblad, Y. Togano, M. Vandebrouck, P. Velho, F. Wamers, H. Weick, C. Wheldon, G.L. Wilson, J.S. Winfield, P. Woods, M. Zhukov, and K. Zuber

Subjects
Physics, QC1-999
Abstract

The quasi-free scattering reactions 11C(p,2p) and 10,11,12C(p,pn) have been studied in inverse kinematics at beam energies of 300–400 MeV/u at the R3B-LAND setup. The outgoing proton-proton and proton-neutron pairs were detected in coincidence with the reaction fragments in kinematically complete measurements. The efficiency to detect these pairs has been obtained from GEANT4 simulations which were tested using the 12C(p,2p) and 12C(p,pn) reactions. Experimental cross sections and momentum distributions have been obtained and compared to DWIA calculations based on eikonal theory. The new results reported here are combined with previously published cross sections for quasi-free scattering from oxygen and nitrogen isotopes and together they enable a systematic study of the reduction of single-particle strength compared to predictions of the shell model over a wide neutron-to-proton asymmetry range. The combined reduction factors show a weak or no dependence on isospin asymmetry, in contrast to the strong dependency reported in nucleon-removal reactions induced by nuclear targets at lower energies. However, the reduction factors for (p,2p) are found to be 'significantly smaller than for (p,pn) reactions for all investigated nuclei. Keywords: Quasi-free scattering, Inverse kinematics, Shell model, Spectroscopic factors

Published
2019
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5. Neutron skin and signature of the N = 14 shell gap found from measured proton radii of 17−22N

Author

S. Bagchi, R. Kanungo, W. Horiuchi, G. Hagen, T.D. Morris, S.R. Stroberg, T. Suzuki, F. Ameil, J. Atkinson, Y. Ayyad, D. Cortina-Gil, I. Dillmann, A. Estradé, A. Evdokimov, F. Farinon, H. Geissel, G. Guastalla, R. Janik, S. Kaur, R. Knöbel, J. Kurcewicz, Yu.A. Litvinov, M. Marta, M. Mostazo, I. Mukha, C. Nociforo, H.J. Ong, S. Pietri, A. Prochazka, C. Scheidenberger, B. Sitar, P. Strmen, M. Takechi, J. Tanaka, Y. Tanaka, I. Tanihata, S. Terashima, J. Vargas, H. Weick, and J.S. Winfield

Subjects
Physics, QC1-999
Abstract

A thick neutron skin emerges from the first determination of root mean square radii of the proton distributions for 17−22N from charge changing cross section measurements around 900A MeV at GSI. Neutron halo effects are signalled for 22N from an increase in the proton and matter radii. The radii suggest an unconventional shell gap at N = 14 arising from the attractive proton–neutron tensor interaction, in good agreement with shell model calculations. Ab initio, in-medium similarity re-normalization group, calculations with a state-of-the-art chiral nucleon–nucleon and three-nucleon interaction reproduce well the data approaching the neutron drip-line isotopes but are challenged in explaining the complete isotopic trend of the radii. Keywords: Proton and matter radii, Neutron skin, Magic number, Shell model, Ab initio theory, Radioactive beams

Published
2019
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6. Manifestation of the Berry phase in the atomic nucleus 213Pb

Author

J.J. Valiente-Dobón, A. Gottardo, G. Benzoni, A. Gadea, S. Lunardi, A. Algora, G. de Angelis, D. Bazzacco, J. Benlliure, P. Boutachkov, A. Bracco, A.M. Bruce, F. Camera, E. Casarejos, M.L. Cortés, F.C.L. Crespi, A. Corsi, C. Domingo-Pardo, M. Doncel, T. Engert, H. Geissel, J. Gerl, A. Goasduff, N. Goel, M. Górska, J. Grebosz, E. Gregor, T. Habermann, S. Klupp, I. Kojouharov, N. Kurz, S.M. Lenzi, S. Leoni, S. Mandal, R. Menegazzo, D. Mengoni, B. Million, A.I. Morales, D.R. Napoli, F. Naqvi, C. Nociforo, M. Pfützner, S. Pietri, Zs. Podolyák, A. Prochazka, F. Recchia, P.H. Regan, D. Rudolph, E. Sahin, H. Schaffner, A. Sharma, B. Sitar, D. Siwal, P. Strmen, I. Szarka, C.A. Ur, P.M. Walker, H. Weick, O. Wieland, H.-J. Wollersheim, and P. Van Isacker

Subjects
Physics, QC1-999
Abstract

The neutron-rich 213Pb isotope was produced in the fragmentation of a primary 1 GeV A 238U beam, separated in FRS in mass and atomic number, and then implanted for isomer decay γ-ray spectroscopy with the RISING setup at GSI. A newly observed isomer and its measured decay properties indicate that states in 213Pb are characterized by the seniority quantum number that counts the nucleons not in pairs coupled to angular momentum J=0. The conservation of seniority is a consequence of a geometric phase associated with particle-hole conjugation, which becomes observable in semi-magic nuclei where nucleons half-fill the valence shell. The γ-ray spectroscopic observables in 213Pb are thus found to be driven by two mechanisms, particle-hole conjugation and seniority conservation, which are intertwined through a Berry phase.

Published
2021
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7. Low-lying electric dipole γ-continuum for the unstable 62,64Fe nuclei: Strength evolution with neutron number

Author

R. Avigo, O. Wieland, A. Bracco, F. Camera, F. Ameil, T. Arici, A. Ataç, D. Barrientos, D. Bazzacco, P. Bednarczyk, G. Benzoni, B. Birkenbach, N. Blasi, H.C. Boston, S. Bottoni, S. Brambilla, B. Bruyneel, M. Ciemała, E. Clément, M.L. Cortés, F.C.L. Crespi, D.M. Cullen, D. Curien, F. Didierjean, C. Domingo-Pardo, G. Duchêne, J. Eberth, A. Görgen, A. Gadea, J. Gerl, N. Goel, P. Golubev, V. González, M. Górska, A. Gottardo, E. Gregor, G. Guastalla, T. Habermann, L.J. Harkness-Brennan, A. Jungclaus, M. Kmiecik, I. Kojouharov, W. Korten, N. Kurz, M. Labiche, N. Lalović, S. Leoni, M. Lettmann, A. Maj, R. Menegazzo, D. Mengoni, E. Merchan, B. Million, A.I. Morales, D.R. Napoli, C. Nociforo, J. Nyberg, N. Pietralla, S. Pietri, Zs. Podolyák, V.Yu. Ponomarev, A. Pullia, B. Quintana, G. Rainovski, D. Ralet, F. Recchia, M. Reese, P. Regan, P. Reiter, S. Riboldi, D. Rudolph, M.D. Salsac, E. Sanchis, L.G. Sarmiento, H. Schaffner, J. Simpson, O. Stezowski, J.J. Valiente-Dobón, and H.J. Wollersheim

Subjects
64Fe, 62Fe, Nuclear structure, Dipole excitation around neutron threshold, Physics, QC1-999
Abstract

The γ-ray emission from the nuclei 62,64Fe following Coulomb excitation at bombarding energy of 400-440 AMeV was measured with special focus on E1 transitions in the energy region 4-8 MeV. The unstable neutron-rich nuclei 62,64Fe were produced at the FAIR-GSI laboratories and selected with the FRS spectrometer. The γ decay was detected with AGATA. From the measured γ-ray spectra the summed E1 strength is extracted and compared to microscopic quasi-particle phonon model calculations. The trend of the E1 strength with increasing neutron number is found to be fairly well reproduced with calculations that assume a rather complex structure of the 1− states (three-phonon states) inducing a strong fragmentation of the E1 nuclear response below the neutron binding energy.

Published
2020
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8. Probing the Z = 6 spin-orbit shell gap with (p,2p) quasi-free scattering reactions

Author

I. Syndikus, M. Petri, A.O. Macchiavelli, S. Paschalis, C.A. Bertulani, T. Aumann, H. Alvarez-Pol, L. Atar, S. Beceiro-Novo, J. Benlliure, J.M. Boillos, K. Boretzky, M.J.G. Borge, B.A. Brown, M. Caamaño, C. Caesar, E. Casarejos, W. Catford, J. Cederkall, S. Chakraborty, L.V. Chulkov, D. Cortina-Gil, E. Cravo, R. Crespo, U. Datta Pramanik, I. Dillmann, P. Díaz Fernández, Z. Elekes, J. Enders, F. Farinon, L.M. Fraile, D. Galaviz, H. Geissel, R. Gernhäuser, P. Golubev, K. Göbel, M. Heil, M. Heine, A. Heinz, A. Henriques, M. Holl, H.T. Johansson, B. Jonson, N. Kalantar-Nayestanaki, R. Kanungo, A. Kelic-Heil, T. Kröll, N. Kurz, C. Langer, T. Le Bleis, J. Machado, J. Marganiec-Gałązka, E. Nacher, T. Nilsson, C. Nociforo, V. Panin, A. Perea, S.B. Pietri, R. Plag, A. Rahaman, R. Reifarth, A. Revel, G. Ribeiro, C. Rigollet, D.M. Rossi, D. Savran, H. Scheit, H. Simon, O. Sorlin, O. Tengblad, Y. Togano, M. Vandebrouck, V. Volkov, F. Wamers, C. Wheldon, G.L. Wilson, J.S. Winfield, H. Weick, P. Woods, D. Yakorev, M. Zhukov, A. Zilges, and K. Zuber

Subjects
Quasi-free scattering reactions, Magic numbers, Spin-orbit splitting, Tensor force, Shell evolution, Exotic nuclei, Physics, QC1-999
Abstract

The evolution of the traditional nuclear magic numbers away from the valley of stability is an active field of research. Experimental efforts focus on providing key spectroscopic information that will shed light into the structure of exotic nuclei and understanding the driving mechanism behind the shell evolution. In this work, we investigate the Z=6 spin-orbit shell gap towards the neutron dripline. To do so, we employed NA(p,2p)CA−1 quasi-free scattering reactions to measure the proton component of the 21+ state of 16,18,20C. The experimental findings support the notion of a moderate reduction of the proton 1p1/2−1p3/2 spin-orbit splitting, at variance to recent claims for a prevalent Z=6 magic number towards the neutron dripline.

Published
2020
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9. First measurement of isoscalar giant resonances in a stored-beam experiment

Author

J.C. Zamora, T. Aumann, S. Bagchi, S. Bönig, M. Csatlós, I. Dillmann, C. Dimopoulou, P. Egelhof, V. Eremin, T. Furuno, H. Geissel, R. Gernhäuser, M.N. Harakeh, A.-L. Hartig, S. Ilieva, N. Kalantar-Nayestanaki, O. Kiselev, H. Kollmus, C. Kozhuharov, A. Krasznahorkay, Th. Kröll, M. Kuilman, S. Litvinov, Yu.A. Litvinov, M. Mahjour-Shafiei, M. Mutterer, D. Nagae, M.A. Najafi, C. Nociforo, F. Nolden, U. Popp, C. Rigollet, S. Roy, C. Scheidenberger, M. von Schmid, M. Steck, B. Streicher, L. Stuhl, M. Thürauf, T. Uesaka, H. Weick, J.S. Winfield, D. Winters, P.J. Woods, T. Yamaguchi, K. Yue, and J. Zenihiro

Subjects
Physics, QC1-999
Abstract

A new technique developed for measuring nuclear reactions at low momentum transfer with stored beams in inverse kinematics was successfully used to study isoscalar giant resonances. The experiment was carried out at the experimental heavy-ion storage ring (ESR) at the GSI facility using a stored 58Ni beam at 100 MeV/u and an internal helium gas-jet target. In these measurements, inelastically scattered α-recoils at very forward center-of-mass angles (θcm≤1.5°) were detected with a dedicated setup, including ultra-high vacuum compatible detectors. Experimental results indicate a dominant contribution of the isoscalar giant monopole resonance at this very forward angular range. It was found that the monopole contribution exhausts 79−11+12% of the energy-weighted sum rule (EWSR), which agrees with measurements performed in normal kinematics. This opens up the opportunity to investigate the giant resonances in a large domain of unstable and exotic nuclei in the near future. It is a fundamental milestone towards new nuclear reaction studies with stored ion beams. Keywords: Storage ring, Inverse kinematics, Isoscalar giant resonances

Published
2016
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10. New test of modulated electron capture decay of hydrogen-like 142Pm ions: Precision measurement of purely exponential decay

Author

F.C. Ozturk, B. Akkus, D. Atanasov, H. Beyer, F. Bosch, D. Boutin, C. Brandau, P. Bühler, R.B. Cakirli, R.J. Chen, W.D. Chen, X.C. Chen, I. Dillmann, C. Dimopoulou, W. Enders, H.G. Essel, T. Faestermann, O. Forstner, B.S. Gao, H. Geissel, R. Gernhäuser, R.E. Grisenti, A. Gumberidze, S. Hagmann, T. Heftrich, M. Heil, M.O. Herdrich, P.-M. Hillenbrand, T. Izumikawa, P. Kienle, C. Klaushofer, C. Kleffner, C. Kozhuharov, R.K. Knöbel, O. Kovalenko, S. Kreim, T. Kühl, C. Lederer-Woods, M. Lestinsky, S.A. Litvinov, Yu.A. Litvinov, Z. Liu, X.W. Ma, L. Maier, B. Mei, H. Miura, I. Mukha, A. Najafi, D. Nagae, T. Nishimura, C. Nociforo, F. Nolden, T. Ohtsubo, Y. Oktem, S. Omika, A. Ozawa, N. Petridis, J. Piotrowski, R. Reifarth, J. Rossbach, R. Sánchez, M.S. Sanjari, C. Scheidenberger, R.S. Sidhu, H. Simon, U. Spillmann, M. Steck, Th. Stöhlker, B.H. Sun, L.A. Susam, F. Suzaki, T. Suzuki, S.Yu. Torilov, C. Trageser, M. Trassinelli, S. Trotsenko, X.L. Tu, P.M. Walker, M. Wang, G. Weber, H. Weick, N. Winckler, D.F.A. Winters, P.J. Woods, T. Yamaguchi, X.D. Xu, X.L. Yan, J.C. Yang, Y.J. Yuan, Y.H. Zhang, and X.H. Zhou

Subjects
Physics, QC1-999
Abstract

An experiment addressing electron capture (EC) decay of hydrogen-like Pm60+142 ions has been conducted at the experimental storage ring (ESR) at GSI. The decay appears to be purely exponential and no modulations were observed. Decay times for about 9000 individual EC decays have been measured by applying the single-ion decay spectroscopy method. Both visually and automatically analysed data can be described by a single exponential decay with decay constants of 0.0126(7)s−1 for automatic analysis and 0.0141(7)s−1 for manual analysis. If a modulation superimposed on the exponential decay curve is assumed, the best fit gives a modulation amplitude of merely 0.019(15), which is compatible with zero and by 4.9 standard deviations smaller than in the original observation which had an amplitude of 0.23(4). Keywords: Two body weak decay, Orbital electron capture, Single particle decay spectroscopy, Heavy ion storage ring

Published
2019
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11. Coulomb and nuclear excitations of narrow resonances in 17Ne

Author

J. Marganiec, F. Wamers, F. Aksouh, Yu. Aksyutina, H. Álvarez-Pol, T. Aumann, S. Beceiro-Novo, C.A. Bertulani, K. Boretzky, M.J.G. Borge, M. Chartier, A. Chatillon, L.V. Chulkov, D. Cortina-Gil, H. Emling, O. Ershova, L.M. Fraile, H.O.U. Fynbo, D. Galaviz, H. Geissel, M. Heil, D.H.H. Hoffmann, J. Hoffmann, H.T. Johansson, B. Jonson, C. Karagiannis, O.A. Kiselev, J.V. Kratz, R. Kulessa, N. Kurz, C. Langer, M. Lantz, T. Le Bleis, R. Lemmon, Yu.A. Litvinov, K. Mahata, C. Müntz, T. Nilsson, C. Nociforo, G. Nyman, W. Ott, V. Panin, S. Paschalis, A. Perea, R. Plag, R. Reifarth, A. Richter, C. Rodriguez-Tajes, D. Rossi, K. Riisager, D. Savran, G. Schrieder, H. Simon, J. Stroth, K. Sümmerer, O. Tengblad, S. Typel, H. Weick, M. Wiescher, and C. Wimmer

Subjects
Physics, QC1-999
Abstract

New experimental data for dissociation of relativistic 17Ne projectiles incident on targets of lead, carbon, and polyethylene targets at GSI are presented. Special attention is paid to the excitation and decay of narrow resonant states in 17Ne. Distributions of internal energy in the O15+p+p three-body system have been determined together with angular and partial-energy correlations between the decay products in different energy regions. The analysis was done using existing experimental data on 17Ne and its mirror nucleus 17N. The isobaric multiplet mass equation is used for assignment of observed resonances and their spins and parities. A combination of data from the heavy and light targets yielded cross sections and transition probabilities for the Coulomb excitations of the narrow resonant states. The resulting transition probabilities provide information relevant for a better understanding of the 17Ne structure.

Published
2016
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12. First direct mass measurements of stored neutron-rich 129,130,131Cd isotopes with FRS-ESR

Author

R. Knöbel, M. Diwisch, F. Bosch, D. Boutin, L. Chen, C. Dimopoulou, A. Dolinskii, B. Franczak, B. Franzke, H. Geissel, M. Hausmann, C. Kozhuharov, J. Kurcewicz, S.A. Litvinov, G. Martinez-Pinedo, M. Matoš, M. Mazzocco, G. Münzenberg, S. Nakajima, C. Nociforo, F. Nolden, T. Ohtsubo, A. Ozawa, Z. Patyk, W.R. Plaß, C. Scheidenberger, J. Stadlmann, M. Steck, B. Sun, T. Suzuki, P.M. Walker, H. Weick, M.-R. Wu, M. Winkler, and T. Yamaguchi

Subjects
In-flight separation, Storage ring, Isochronous mass spectrometry, Shell closure at N=82, 129,130,131Cd isotopes, Mass models, Physics, QC1-999
Abstract

A 410 MeV/u 238U projectile beam was used to create cadmium isotopes via abrasion-fission in a beryllium target placed at the entrance of the in-flight separator FRS at GSI. The fission fragments were separated by the FRS and injected into the isochronous storage ring ESR for mass measurements. Isochronous Mass Spectrometry (IMS) was performed under two different experimental conditions, with and without Bρ-tagging at the high-resolution central focal plane of the FRS. In the experiment with Bρ-tagging the magnetic rigidity of the injected fragments was determined with an accuracy of 2⋅10−4. A new method of data analysis, which uses a correlation matrix for the combined data set from both experiments, has provided experimental mass values of 25 rare isotopes for the first time. The high sensitivity and selectivity of the method have given access to nuclides detected with a rate of a few atoms per week. In this letter we present for the 129,130,131Cd isotopes mass values directly measured for the first time. The experimental mass values of cadmium as well as for tellurium and tin isotopes show a pronounced shell effect towards and at N=82. Shell quenching cannot be deduced from a single new mass value, nor by a better agreement with a theoretical model which explicitly takes into account a quenching feature. This is in agreement with the conclusion from γ-ray spectroscopy and confirms modern shell-model calculations.

Published
2016
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13. Precision of the PET activity range during irradiation with

Author

D, Kostyleva, S, Purushothaman, P, Dendooven, E, Haettner, H, Geissel, I, Ozoemelam, C, Schuy, U, Weber, D, Boscolo, T, Dickel, V, Drozd, C, Graeff, B, Franczak, C, Hornung, F, Horst, E, Kazantseva, N, Kuzminchuk-Feuerstein, I, Mukha, C, Nociforo, S, Pietri, C A, Reidel, H, Roesch, Y K, Tanaka, H, Weick, J, Zhao, M, Durante, K, Parodi, and C, Scheidenberger

Published
2022

14. Proton Distribution Radii of O16–24 : Signatures of New Shell Closures and Neutron Skin

Author

S. Kaur, R. Kanungo, W. Horiuchi, G. Hagen, J. D. Holt, B. S. Hu, T. Miyagi, T. Suzuki, F. Ameil, J. Atkinson, Y. Ayyad, S. Bagchi, D. Cortina-Gil, I. Dillmann, A. Estradé, A. Evdokimov, F. Farinon, H. Geissel, G. Guastalla, R. Janik, R. Knöbel, J. Kurcewicz, Yu. A. Litvinov, M. Marta, M. Mostazo, I. Mukha, C. Nociforo, H. J. Ong, T. Otsuka, S. Pietri, A. Prochazka, C. Scheidenberger, B. Sitar, P. Strmen, M. Takechi, J. Tanaka, I. Tanihata, S. Terashima, J. Vargas, H. Weick, and J. S. Winfield

Subjects
General Physics and Astronomy
Published
2022

15. In-beam test results of the Super-FRS GEM-TPC detector prototype with relativistic uranium ion beam

Author

M. Luoma, F. García, J. Äystö, T. Blatz, D. Chokheli, H. Flemming, K. Götzen, T. Grahn, A. Jokinen, C. Karagiannis, N. Kurz, S. Löchner, C. Nociforo, S. Rinta-Antila, C.J. Schmidt, H. Simon, R. Turpeinen, B. Voss, P. Wieczorek, M. Winkler, and Helsinki Institute of Physics

Subjects
clusterization, Nuclear and High Energy Physics, ilmaisimet, super-FRS, tutkimuslaitteet, tracking, ydinfysiikka, 114 Physical sciences, GEM-TPC, Instrumentation, FAIR
Abstract

As an essential part of the Super-FRS particle identification, the GEM-TPC detector in a twin field-cage configuration will provide position information at up to 1 MHz counting rate with a spatial resolution < 1 mm and with tracking efficiency >95 %. This detector is designed to provide particle-beam tracking information of projectiles ranging from protons to uranium. The performance of the GEM-TPC detector in a single field-cage configuration and newly integrated AWAGS readout electronics with a differential output was studied at the FRS for the response to the uranium beam at 850 MeV/u with intensity up to 1000 ions/spill. The result shows that a clusterization algorithm developed for this analysis works properly. The spatial resolution of 0.74–0.81 mm, a detection efficiency >99 %, and a tracking efficiency >96 % were found. This work describes the methodology used to achieve such results in detail. peerReviewed

Published
2023

16. Influence of proton and neutron deformed shells on the asymmetric fission of thorium isotopes

Author

A. Chatillon, J. Taïeb, A. Heinz, H. Alvarez-Pol, L. Audouin, Y. Ayyad, G. Bélier, J. Benlliure, G. Boutoux, M. Caamaño, E. Casarejos, D. Cortina-Gil, A. Ebran, F. Farget, B. Fernández-Domínguez, T. Gorbinet, L. Grente, H. T. Johansson, B. Jurado, A. Kelić-Heil, N. Kurz, B. Laurent, J.-F. Martin, C. Nociforo, C. Paradela, E. Pellereau, S. Pietri, A. Prochazka, J. L. Rodríguez-Sánchez, D. Rossi, H. Simon, L. Tassan-Got, J. Vargas, B. Voss, H. Weick, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Paris-Saclay, 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), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Deux Infinis Bordeaux (LP2I - Bordeaux), and Université de Bordeaux (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

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

International audience; Mean values of the number of protons and neutrons of the primary fission fragments at scission are determined for the asymmetric fission of 16 fissioning isotopes, from Ac219 up to Np238. Our results confirm that the main asymmetric fission mode around the heavier uranium isotopes is indeed characterized by an average atomic number around 〈ZH〉=54 in the heavy fission fragments. However, they also unambiguously show a stabilization effect in the light fission fragments around 〈NL〉=52–54 in the neutron-deficient thorium and actinium isotopes. This is a clear signature that these deformed proton and neutron shell closures around 54 play a major role in the nuclear fission process. The evolution along the thorium chain shows that the neutron shell appears to be dominant in the asymmetric fission of the lighter thorium isotopes, in contrast to the heavier thorium isotopes for which the stabilization originates from the proton shell.

Published
2022

17. Fission-fragment yields measured in Coulomb-induced fission of 234,235,236,238U and 237,238Np with the R3B/SOFIA setup

Author

A. Chatillon, G. Boutoux, T. Gorbinet, L. Grente, J.-F. Martin, E. Pellereau, J. Taieb, H. Alvarez-Pol, L. Audouin, Y. Ayyad, G. Bélier, J. Benlliure, M. Caamaño, E. Casarejos, D. Cortina-Gil, A. Ebran, F. Farget, B. Fernández-Domínguez, A. Heinz, H. T. Johansson, B. Jurado, A. Kelić-Heil, N. Kurz, B. Laurent, B. Loeher, C. Nociforo, C. Paradela, S. Pietri, A. Prochazka, D. Ramos, J. L. Rodríguez-Sànchez, C. Rodriguez, D. Rossi, H. Simon, L. Tassan-Got, H. Toernqvist, J. Vargas, B. Voss, and H. Weick

Subjects
General Medicine
Abstract

Low energy fission of 234,235,236,238U and 237,238Np radioactive beams, provided by the GSI/FRS facility, has been studied using the R3B/SOFIA setup. The latter allows, on an event-by-event basis, to simultaneously identify, in terms of their mass and atomic numbers, the fissioning nucleus in coincidence with both fission fragments after prompt-neutron emission. This presentation reports on new results on elemental, isobaric and isotopic yields.

Published
2023

18. Fission-fragment yields and prompt-neutron multiplicity for Coulomb-induced fission of U234,235 and Np237,238

Author

S. Pietri, J. Benlliure, A. Chatillon, G. Boutoux, A. Kelic-Heil, D. M. Rossi, B. Jurado, F. Farget, A. Prochazka, C. Nociforo, J. F. Martin, E. Casarejos, Bernd Voss, B. Laurent, H. Alvarez-Pol, M. Caamaño, T. Gorbinet, Y. Ayyad, G. Belier, L. Grente, J. Vargas, D. Cortina-Gil, E. Pellereau, C. Paradela, A. Ebran, B. Fernández-Domínguez, L. Tassan-Got, Helmut Weick, L. Audouin, Andreas Martin Heinz, Håkan Johansson, N. Kurz, J. L. Rodriguez-Sanchez, J. Taieb, and Herbert A. Simon

Subjects
Physics, Proton, 010308 nuclear & particles physics, Fission, Nuclear Theory, 01 natural sciences, Nuclear physics, medicine.anatomical_structure, Prompt neutron, 0103 physical sciences, medicine, Neutron, Atomic number, Multiplicity (chemistry), Nuclear Experiment, 010306 general physics, Nucleus, Excitation
Abstract

Low-energy fission of and radioactive beams, provided by the Fragment Separator (FRS) of the GSI Helmholtzzentrum fur Schwerionenforschung facility (GSI), has been studied using the Reactions with Relativistic Radioactive Beams / Studies on Fission with Aladin (R3B/SOFIA) setup. The latter allows us, on an event-by-event basis, to simultaneously identify, in terms of their mass and atomic numbers, the fissioning nucleus in coincidence with both fission fragments after prompt-neutron emission. This article reports new results on elemental, isotonic, isobaric, and isotopic yields. Moreover, the high accuracy of our data allowed us to study in detail proton even-odd staggering, from elemental yields; neutron excess, from isotopic yields; and total prompt-neutron multiplicity, from the difference of masses of the fissioning nucleus and fission fragments. These results are then compared to previous experimental data in order to probe how these fission observables change as function of the excitation energy and atomic and neutron numbers of the compound nucleus.

Published
2021

19. Neutron capture cross sections of light neutron-rich nuclei relevant for r-process nucleosynthesis

Author

M. Heine, Th. Kröll, S. Chakraborty, Rene Reifarth, Stefan Typel, P. Díaz Fernández, D. M. Rossi, Ushasi Datta, Marielle Chartier, Ralf Plag, J. Marganiec, A. Bhattacharyya, Catherine Rigollet, Christoph Langer, V. Panin, M. V. Ricciardi, C. Nociforo, P. Das, R. Krücken, Yvonne Leifels, S. Beceiro-Novo, Herbert A. Simon, Anisur Rahaman, C. Caesar, H. Geissel, J. S. Winfield, Andreas Wagner, Nasser Kalantar-Nayestanaki, Björn Jonson, H. Emling, T. Le Bleis, W. N. Catford, Thomas Aumann, D. Cortina-Gil, Stefanos Paschalis, Yasuhiro Togano, G. Münzenberg, Yutaka Utsuno, C. Scheidenberger, Helmut Weick, Håkan T Johansson, H. Scheit, D. González-Díaz, J. Kurcewicz, K. Boretzky, G. De. Angelis, B. V. Carlson, Thomas Nilsson, F. Wamers, Nuclear Energy, Institut Pluridisciplinaire Hubert Curien (IPHC), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Neutron capture, 010308 nuclear & particles physics, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, r-process nucleosynthesis, Dissociation (chemistry), Nuclear physics, Reaction rate, Nucleosynthesis, neutron-rich nuclei, 0103 physical sciences, Neutron cross section, r-process, Neutron, Hauser-Feshbach, 010306 general physics, Ground state, Nuclear Experiment
Abstract

International audience; The measurements of neutron capture cross sections of neutron-rich nuclei are challenging but essential for understanding nucleosynthesis and stellar evolution processes in the explosive burning scenario. In the quest of r-process abundances, according to the neutrino-driven-wind model, light neutron-rich unstable nuclei may play a significant role as seed nuclei that influence the abundance pattern. Hence, experimental data for neutron capture cross sections of neutron-rich nuclei are needed. Coulomb dissociation of radioactive ion beams at intermediate energy is a powerful indirect method for inferring capture cross section. As a test case for validation of the indirect method, the neutron capture cross section (n, γ) for C14 was inferred from the Coulomb dissociation of C15 at intermediate energy (600A MeV). A comparison between different theoretical approaches and experimental results for the reaction is discussed. We report for the first time experimental reaction cross sections of Na28(n,γ)Na29, Na29(n,γ)Na30, Mg32(n,γ)Mg33, and Al34(n,γ)Al35. The reaction cross sections were inferred indirectly through Coulomb dissociation of Na29,30, Mg33, and Al35 at incident projectile energies around 400–430 A MeV using the FRS-LAND setup at GSI, Darmstadt. The neutron capture cross sections were obtained from the photoabsorption cross sections with the aid of the detailed balance theorem. The reaction rates for the neutron-rich Na, Mg, Al nuclei at typical r-process temperatures were obtained from the measured (n,γ) capture cross sections. The measured neutron capture reaction rates of the neutron-rich nuclei, Na28, Na29, and Al34 are significantly lower than those predicted by the Hauser-Feshbach decay model. A similar trend was observed earlier for C17 and N19 but in the case of C14(n,γ)C15 the trend is opposite. The situation is more complicated when the ground state has a multi-particle-hole configuration. For Mg32, the measured cross section is about 40–90% higher than the Hauser-Feshbach prediction.

Published
2021

21. Mass measurements of As, Se, and Br nuclei, and their implication on the proton-neutron interaction strength toward the N=Z line

Author

Emma Haettner, Zygmunt Patyk, Mikhail I. Yavor, Daler Amanbayev, D. Nichita, Christoph Scheidenberger, S. Pietri, Timo Dickel, Sönke Beck, Helmut Weick, D. A. Kostyleva, A. A. Bezbakh, Anu Kankainen, Jean-Paul Hucka, O. Charviakova, S. A. Krupko, G. Stanic, C. Nociforo, S. Purushothaman, I. A. Muzalevskii, Julian Bergmann, M. N. Harakeh, P. G. Sharov, Nasser Kalantar-Nayestanaki, M. Dehghan, Paul Constantin, R. Knöbel, V. Chudoba, Christine Hornung, M. Vencelj, A. State, O. Hall, G. Kripko-Koncz, Moritz P. Reiter, A. Mollaebrahimi, M. Pfützner, S. Ayet San Andrés, Wolfgang R. Plaß, F. Schirru, N. Kurkova, L. Gröf, L. V. Grigorenko, N. Kuzminchuk, D. L. Balabanski, A. S. Fomichev, J. Zhao, Y. K. Tanaka, O. Kiselev, Hans Geissel, Z. Brencic, Israel Mardor, I. Mukha, H. Roesch, Ivan Miskun, S. Bagchi, A. Spataru, Research unit Nuclear & Hadron Physics, and Energy and Sustainability Research Institute Groni

Subjects
nucl-th, Nuclear Theory, FOS: Physical sciences, Interaction strength, nucl-ex, Mass spectrometry, 01 natural sciences, 7. Clean energy, arseeni, Ion, Nuclear Theory (nucl-th), Nuclear physics, Fragmentation (mass spectrometry), 0103 physical sciences, ddc:530, Neutron, bromi, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Isotope, 010308 nuclear & particles physics, Mass measurement, Atomic mass, seleeni, ydinfysiikka
Abstract

Mass measurements of the $^{69}$As, $^{70,71}$Se and $^{71}$Br isotopes, produced via fragmentation of a $^{124}$Xe primary beam at the FRS at GSI, have been performed with the multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) of the FRS Ion Catcher with an unprecedented mass resolving power of almost 1,000,000. For the $^{69}$As isotope, this is the first direct mass measurement. A mass uncertainty of 22 keV was achieved with only 10 events. For the $^{70}$Se isotope, a mass uncertainty of 2.6 keV was obtained, corresponding to a relative accuracy of $\delta$m/m = 4.0$\times 10^{-8}$, with less than 500 events. The masses of the $^{71}$Se and $^{71}$Br isotopes were measured with an uncertainty of 23 and 16 keV, respectively. Our results for the $^{70,71}$Se and $^{71}$Br isotopes agree with the 2016 Atomic Mass Evaluation, and our result for the $^{69}$As isotope resolves the discrepancy between previous indirect measurements. We measured also the mass of $^{14}$N$^{15}$N$^{40}$Ar (A=69) with a relative accuracy of $\delta$m/m = 1.7$\times 10^{-8}$, the highest yet achieved with a MR-TOF-MS. Our results show that the measured restrengthening of the proton-neutron interaction ($\delta$V$_{pn}$) for odd-odd nuclei at the N=Z line above Z=29 (recently extended to Z=37) is hardly evident at N-Z=2, and not evident at N-Z=4. Nevertheless, detailed structure of $\delta$V$_{pn}$ along the N-Z=2 and N-Z=4 lines, confirmed by our mass measurements, may provide a hint regarding the ongoing $\approx$500 keV discrepancy in the mass value of the $^{70}$Br isotope, which prevents including it in the world average of ${Ft}$-value for superallowed 0$^+\rightarrow$ 0$^+$ $\beta$ decays. The reported work sets the stage for mass measurements with the FRS Ion Catcher of nuclei at and beyond the N=Z line in the same region of the nuclear chart, including the $^{70}$Br isotope., Comment: 11 pages, 4 figures, accepted for publication at Physical Review C

Published
2021

22. Manifestation of the Berry phase in the atomic nucleus 213Pb

Author

S. Klupp, A. Algora, Roberto Menegazzo, D. Mengoni, F. Naqvi, J. J. Valiente-Dobón, S. Pietri, T. Habermann, J. Benlliure, Branislav Sitar, Alison Bruce, A. Bracco, P. Van Isacker, N. Kurz, Andrea Corsi, E. Sahin, Dirk Rudolph, Imrich Szarka, Helmut Weick, Zs. Podolyák, J. Gerl, J. Grebosz, Davinder Siwal, S. K. Mandal, S. Leoni, T. Engert, D. Bazzacco, A. Prochazka, M. Górska, F. Recchia, S. Lunardi, D. R. Napoli, Hans Geissel, P. Boutachkov, A. Gottardo, F. Camera, Enrique Casarejos, I. Kojouharov, P. H. Regan, E. Gregor, Oliver Wieland, H. J. Wollersheim, A. Sharma, G. de Angelis, C. Nociforo, F. C. L. Crespi, A. Goasduff, C. Domingo-Pardo, A. I. Morales, M. Pfützner, B. Million, G. Benzoni, M. L. Cortés, Philip M Walker, C. A. Ur, Peter Strmen, H. Schaffner, A. Gadea, Maria Doncel, N. Goel, S. M. Lenzi, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear and High Energy Physics, Angular momentum, nucl-th, Nuclear Theory, isomeric decays, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucl-ex, 01 natural sciences, Nuclear Theory (nucl-th), 0103 physical sciences, Subatomic Physics, Nuclear Physics - Experiment, ddc:530, 22 Física, Nuclear Experiment (nucl-ex), 010306 general physics, Spectroscopy, Nuclear Experiment, Physics, Isotope, 010308 nuclear & particles physics, 2207 Física Atómica y Nuclear, Quantum number, lcsh:QC1-999, relativistic projectile fragmentation, ddc, Geometric phase, gamma-ray spectroscopy, Nuclear Physics - Theory, Atomic nucleus, Atomic number, Atomic physics, Nucleon, lcsh:Physics
Abstract

Physics letters / B 816, 136183 (2021). doi:10.1016/j.physletb.2021.136183, Published by North-Holland Publ., Amsterdam

Published
2021

23. Evidence for a New Compact Symmetric Fission Mode in Light Thorium Isotopes

Author

Andreas Martin Heinz, M. Caamaño, Enrique Casarejos, A. Ebran, Yassid Ayyad, A. Chatillon, G. Boutoux, J. Taieb, J. Vargas, J. L. Rodriguez-Sanchez, T. Gorbinet, B. Laurent, F. Farget, A. Prochazka, S. Pietri, D. Cortina-Gil, C. Nociforo, C. Paradela, B. Fernández-Domínguez, E. Pellereau, L. Audouin, N. Kurz, Helmut Weick, Håkan T Johansson, L. Grente, Herbert A. Simon, J. Benlliure, H. Alvarez-Pol, D. M. Rossi, Bernd Voss, G. Belier, J. F. Martin, L. Tassan-Got, A. Kelic-Heil, Beatriz Jurado, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Physique Nucléaire d'Orsay (IPNO), 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), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Isotope, Fission, Nuclear Theory, General Physics and Astronomy, Thorium, chemistry.chemical_element, Actinide, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Effective nuclear charge, Physics::Geophysics, Nuclear physics, chemistry, 0103 physical sciences, Multiplicity (chemistry), 010306 general physics, Nuclear Experiment, Bond cleavage, Isotopes of thorium, Nuclear Physics
Abstract

International audience; Taking benefit of the R3B/SOFIA setup to measure the mass and the nuclear charge of both fission fragments in coincidence with the total prompt-neutron multiplicity, the scission configurations are inferred along the thorium chain, from the asymmetric fission in the heavier isotopes to the symmetric fission in the neutron-deficient thorium. Against all expectations, the symmetric scission in the light thorium isotopes shows a compact configuration, which is in total contrast to what is known in the fission of the heavier thorium isotopes and heavier actinides. This new main symmetric scission mode is characterized by a significant drop in deformation energy of the fission fragments of about 19 MeV, compared to the well-known symmetric scission in the uranium-plutonium region.

Published
2020

24. Low-lying electric dipole gamma-continuum for the unstable Fe-62,64 nuclei : Strength evolution with neutron number

Author

Eric Clément, B. Birkenbach, A. I. Morales, D. Bazzacco, H. J. Wollersheim, J. J. Valiente-Dobón, D. M. Cullen, L. J. Harkness-Brennan, M. Kmiecik, Alberto Pullia, C. Domingo-Pardo, Luis Sarmiento, C. Nociforo, N. Goel, B. Bruyneel, G. Rainovski, M.D. Salsac, S. Pietri, Begoña Quintana, J. Simpson, Pavel Golubev, T. Habermann, Johan Nyberg, R. Menegazzo, S. Leoni, M. Reese, V. Yu. Ponomarev, A. Maj, T. Arici, A. Gottardo, N. Kurz, M. Górska, S. Brambilla, I. Kojouharov, E. Merchan, M. L. Cortés, Stefano Riboldi, Enrique Sanchis, N. Lalović, Vicente González, R. Avigo, Norbert Pietralla, P. Reiter, F. Camera, M. Labiche, Zs. Podolyák, J. Gerl, D. Ralet, F. Ameil, Andreas Görgen, A. Gadea, A. Bracco, A. Jungclaus, G. Benzoni, O. Stezowski, Dirk Rudolph, D. Curien, J. Eberth, H. C. Boston, S. Bottoni, W. Korten, F. C. L. Crespi, N. Blasi, H. Schaffner, D. Mengoni, M. Lettmann, G. Duchêne, Diego Barrientos, P. H. Regan, F. Didierjean, M. Ciemala, P. Bednarczyk, G. Guastalla, B. Million, E. Gregor, Oliver Wieland, F. Recchia, D. R. Napoli, A. Atac, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Istituto Nazionale di Fisica Nucleare, Science and Technology Facilities Council (UK), Swedish Research Council, Federal Ministry of Education and Research (Germany), European Commission, Generalitat Valenciana, Ministerio de Economía y Competitividad (España), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Phonon, Astrophysics::High Energy Astrophysical Phenomena, Binding energy, Nuclear Theory, Coulomb excitation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, 64Fe, Dipole excitation around neutron threshold, 62Fe, Subatomär fysik, 0103 physical sciences, Subatomic Physics, ddc:530, Neutron, Nuclear Physics - Experiment, Nuclear structure, 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, 62 Fe, Fe, 64, 64 Fe, lcsh:QC1-999, Dipole, Fe-64, Neutron number, Fe-62, AGATA, Atomic physics, lcsh:Physics
Abstract

6 pags., 4 figs., The γ-ray emission from the nuclei Fe following Coulomb excitation at bombarding energy of 400-440 AMeV was measured with special focus on E1 transitions in the energy region 4-8 MeV. The unstable neutron-rich nuclei Fe were produced at the FAIR-GSI laboratories and selected with the FRS spectrometer. The γ decay was detected with AGATA. From the measured γ-ray spectra the summed E1 strength is extracted and compared to microscopic quasi-particle phonon model calculations. The trend of the E1 strength with increasing neutron number is found to be fairly well reproduced with calculations that assume a rather complex structure of the 1 states (three-phonon states) inducing a strong fragmentation of the E1 nuclear response below the neutron binding energy., This work was partially supported by INFN (Italy) and STFC (UK), the Swedish Research Council (Vetenskapsrådet, VR 2010-147, 2011-5253, and 2016-3969), BMBF NuSTAR-AGATA 05P18RDFN9 and BMBF NuSTAR 05P18RDFN1. The project was co-funded by the European Commission under the 7th Framework Program for RTD (2007-2013) under the Capacities Program (Contract Number 262010, ENSAR). This work was par-tially supported by the Ministry of Science, and Generalitat Valenciana, Spain, under the Grants SEV-2014-0398, FPA2017-84756-C4, PROMETEO/2019/005 and by the EU FEDER funds.

Published
2020

25. Probing the Z = 6 spin-orbit shell gap with (p,2p) quasi-free scattering reactions

Author

A. Henriques, J. S. Winfield, Thomas Nilsson, Rene Reifarth, M. Heine, E. Cravo, L. M. Fraile, Håkan T Johansson, O. Sorlin, L. Chulkov, W. N. Catford, A. Revel, J. Marganiec-Gałązka, Pavel Golubev, H. Scheit, S. Beceiro-Novo, Joakim Cederkäll, R. Gernhäuser, Carlos A. Bertulani, Y. Togano, T. Le Bleis, D. Cortina-Gil, L. Atar, G. L. Wilson, S. Pietri, F. Farinon, Kai Zuber, N. Kurz, Andreas Zilges, V. Volkov, M. Heil, C. Langer, A. Kelic-Heil, R. Plag, Catherine Rigollet, J. Enders, Iris Dillmann, U. Datta Pramanik, Jorge Machado, H. Alvarez-Pol, I. Syndikus, A. O. Macchiavelli, Marina Petri, D. Yakorev, M. Holl, Enrique Casarejos, G. Ribeiro, Mikhail V. Zhukov, Stefanos Paschalis, María José García Borge, Marine Vandebrouck, Deniz Savran, V. Panin, Björn Jonson, Nasser Kalantar-Nayestanaki, Philip Woods, Ángel Perea, C. Wheldon, R. Crespo, Thomas Aumann, Hans Geissel, Z. Elekes, Andreas Martin Heinz, J. M. Boillos, B. A. Brown, D. Galaviz, T. Kröll, S. Chakraborty, K. Göbel, Enrique Nácher, H. Weick, Rituparna Kanungo, P. Díaz Fernández, K. Boretzky, M. Caamaño, Anisur Rahaman, C. Caesar, J. Benlliure, F. Wamers, D. Rossi, Haik Simon, Olof Tengblad, C. Nociforo, 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), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), R$^3$B, Energy and Sustainability Research Institute Groni, Research unit Nuclear & Hadron Physics, Royal Society (UK), Department of Energy (US), Federal Ministry of Education and Research (Germany), State of Hesse, Technische Universität Darmstadt, Helmholtz Association, European Young Investigator Awards, Swedish Research Council, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Xunta de Galicia, German Research Foundation, National Science Foundation (US), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear and High Energy Physics, Quasi-free scattering reactions, Field (physics), Proton, Nuclear Theory, Shell (structure), FOS: Physical sciences, Shell evolution, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Atomic, Nuclear physics, Magic number (programming), Particle and Plasma Physics, 0103 physical sciences, Neutron, Nuclear, ddc:530, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Mathematical Physics, Spin-½, Physics, 010308 nuclear & particles physics, Scattering, Molecular, Spin-orbit splitting, Nuclear & Particles Physics, lcsh:QC1-999, 3. Good health, Valley of stability, Tensor force, Magic numbers, Física nuclear, lcsh:Physics, Astronomical and Space Sciences, Exotic nuclei
Abstract

9 pags., 5 figs., 2 tabs., The evolution of the traditional nuclear magic numbers away from the valley of stability is an active field of research. Experimental efforts focus on providing key spectroscopic information that will shed light into the structure of exotic nuclei and understanding the driving mechanism behind the shell evolution. In this work, we investigate the Z=6 spin-orbit shell gap towards the neutron dripline. To do so, we employed NA(p,2p)CA−1 quasi-free scattering reactions to measure the proton component of the 2 state of C. The experimental findings support the notion of a moderate reduction of the proton 1p−1p spin-orbit splitting, at variance to recent claims for a prevalent Z=6 magic number towards the neutron dripline., This work was supported by the Royal Society award UF150476, UK STFC awards ST/M006433/1 and ST/P003885/1, U.S. Department of Energy, Office of Nuclear Physics, contract No. DE-AC02- 05CH11231 (LBNL), the German Federal Ministry of Education and Research (BMBF projects 05P15RDFN1, 05P15WOFNA and 05P19RDFN1), the GSI-TU Darmstadt cooperation agreement, the State of Hesse through the LOEWE center HIC for FAIR, the Helmholtz-Gemeinschaft through the graduate school HGS-HIRe and Young Investigators Grants, and the Swedish Research Council under contract number 621-2011-5324. This work was also supported by the Spanish research grants (Ministerio Ciencia e Innovación), FPA2015-64969-P, FPA2015-69640-C2-1-P, FPA2017- 87568-P, PGC2018-099746-B-C21, RTI2018-098868-B-I00, Undidad de Excelencia María de Maeztu under project MDM-2016.0692, and the Xunta de Galicia research grant GRC ED431C 2017/54. This work was partly supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Project-ID 279384907 - SFB 1245. C.A.B. acknowledges support from the U.S. NSF Grant No. 1415656, and U.S. DOE Grant No. DE-FG02-08ER41533.

Published
2020

26. A GEM-TPC in twin configuration for the Super-FRS tracking of heavy ions at FAIR

Author

C. Caesar, C. Simons, Ari Jokinen, J. Kunkel, Tuomas Grahn, J. Hoffmann, A. Prochazka, H. Heggen, Sami Rinta-Antila, Bernd Voss, R. Turpeinen, M. Winkler, Harvey A. Risch, N. Kurz, C. Kaya, Herbert A. Simon, Francisco Garcia, C. Nociforo, I. Rusanov, C. J. Schmidt, and Juha Äystö

Subjects
radioactive ion beam, Nuclear and High Energy Physics, Proton, fragment separator, Physics::Instrumentation and Detectors, super-FRS, chemistry.chemical_element, Tracking (particle physics), 01 natural sciences, 7. Clean energy, Particle identification, GSI, Xenon, Optics, 0103 physical sciences, seuranta, Nuclear Experiment, 010306 general physics, Instrumentation, Image resolution, Physics, Time projection chamber, ta114, 010308 nuclear & particles physics, Projectile, business.industry, tracking, fair, time projection chamber, beam adjustment, chemistry, gas electron multiplier, Gas electron multiplier, business
Abstract

The GEM-TPC [1] described herein will be part of the standard beam-diagnostics equipment of the Super-FRS [2] . This chamber will provide tracking information for particle identification at rates up to 1 MHz on an event-by-event basis. The key requirements of operation for these chambers are: close to 100% tracking efficiency under conditions of high counting rate, spatial resolution below 1 mm and a superb large dynamic range covering projectiles from Z=1 up to Z=92. The current prototype consists of two GEM-TPCs inside a single vessel, which are operating independently and have electrical drift fields in opposite directions. The twin configuration is done by flipping one of the GEM-TPCs on the middle plane with respect to the second one. In order to put this development in context, the evolution of previous prototypes will be described and its performances discussed. Finally, this chamber was tested at the University of Jyväskylä accelerator with proton projectiles and at GSI with Uranium, Xenon, fragments and Carbon beams. The results obtained have shown a position resolution between 120 to 300 μm at moderate counting rate under conditions of full tracking efficiency. peerReviewed

Published
2018

27. The (6+) isomer in 102Sn revisited: Neutron and proton effective charges close to the double shell closure

Author

Shunji Nishimura, Yu. A. Litvinov, T. Davinson, H. J. Wollersheim, F. Nebel, K. Straub, T. Habermann, S. Schwertel, T. Faestermann, Igor T. Čeliković, P. Boutachkov, F. Farinon, C. Hinke, P. Strmeň, Hans Geissel, H. Schaffner, M. Karny, F. Nowacki, M. Lewitowicz, H. Grawe, N. Kurz, M. Górska, P. A. Söderström, G. F. Farrelly, Andreas Stolz, Zs. Podolyák, A. Atac, J. Grȩbosz, A. Prochazka, Robert Hoischen, I. Kojouharov, R. Janik, C. Scheidenberger, P. J. Woods, P. H. Regan, S. J. Steer, S. Pietri, S. Myalski, N. Braun, Roman Gernhäuser, M. Böhmer, A. Blazhev, N. Al-Dahan, Johan Nyberg, R. Krücken, A. Kaşkaş, J. Gerl, N. Alkhomashi, L. Maier, N. Goel, C. Nociforo, A. Gottardo, Zhi Liu, Catherine Rigollet, C. Domingo-Pardo, Helmut Weick, P. Doornenbal, Iris Dillmann, A. Parikh, K. Steiger, Th. Kröll, CoSee GmbH [Darmstadt], Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), 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), SUPA School of Physics and Astronomy [Edinburgh], University of Edinburgh, Polish Academy of Sciences (PAN), Department of Physics, University of Surrey, University of Surrey (UNIS), Department of Physics, Faculty of Science, Middle East Technical University, Ankara, Turkey, Department of Fusion Plasma Physics [Stockholm] (KTH), Royal Institute of Technology [Stockholm] (KTH ), University of Cologne, Vinča Institute of Nuclear Sciences, University of Belgrade [Belgrade], Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Comenius University in Bratislava, University of Warsaw (UW), Faculty of Science Astronomy, Ankara University, Tandogan Ankara, TR-06100 Turkey, obasturk@ankara.edu.tr, Polska Akademia Nauk = Polish Academy of Sciences (PAN), RIKEN Nishina Center for Accelerator-Based Science [Wako] (RIKEN RNC), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Uppsala Universitet [Uppsala], Kernfysisch Versneller Instituut (KVI), University of Groningen [Groningen], Uppsala University, Michigan State University [East Lansing], Michigan State University System, RISING, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Blank, B., and Technische Universität München [München] (TUM)

Subjects
Sn, Nuclear and High Energy Physics, Proton, QC1-999, SHELL model, Closure (topology), Shell (structure), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Space (mathematics), 01 natural sciences, Subatomär fysik, Shell model, Fragmentation (mass spectrometry), Subatomic Physics, 0103 physical sciences, ddc:530, Neutron, 010306 general physics, Effective charges near Sn, Physics, 010308 nuclear & particles physics, Effective charges near, Polarization (waves), ddc, Effective charges near Sn-100, Electromagnetic transitions, Effective charges near 100Sn, Atomic physics
Abstract

Physics letters / B 820, 136591 (2021). doi:10.1016/j.physletb.2021.136591, Published by North-Holland Publ., Amsterdam

Published
2021

28. First measurement of isoscalar giant resonances in a stored-beam experiment

Author

I. Dillmann, V. K. Eremin, J. C. Zamora, M. Thürauf, Helmut Weick, M. Mahjour-Shafiei, Manfred Mutterer, Hans Geissel, S. Bagchi, Peter Egelhof, M. Kuilman, M. A. Najafi, D. Nagae, P. J. Woods, Tomohiro Uesaka, Catherine Rigollet, Yu. A. Litvinov, Takayuki Yamaguchi, Th. Kröll, Roman Gernhäuser, C. Nociforo, B. Streicher, Christoph Scheidenberger, Sergey Litvinov, M. Steck, C. Kozhuharov, F. Nolden, L. Stuhl, M.N. Harakeh, Danyal Winters, H. Kollmus, K. Yue, A.-L. Hartig, S. Ilieva, Santosh Roy, S. Bönig, M. Csatlós, Tatsuya Furuno, M. von Schmid, O. Kiselev, Nasser Kalantar-Nayestanaki, Thomas Aumann, Juzo Zenihiro, A. Krasznahorkay, U. Popp, J. S. Winfield, C. Dimopoulou, Research unit Nuclear & Hadron Physics, Theory of Condensed Matter, and Research unit Astroparticle Physics

Subjects
Nuclear reaction, Nuclear and High Energy Physics, Isoscalar, Nuclear Theory, 01 natural sciences, Nuclear physics, INELASTIC ALPHA-SCATTERING, ENERGY, 0103 physical sciences, EXCITATION, NI-58, PARTICLES, Neutron, ddc:530, 010306 general physics, Nuclear Experiment, Physics, NUCLEI, 010308 nuclear & particles physics, Momentum transfer, Resonance, lcsh:QC1-999, Inverse kinematics, Physics::Accelerator Physics, Isoscalar giant resonances, NEUTRON, Sum rule in quantum mechanics, DIPOLE RESONANCE, Atomic physics, Storage ring, Beam (structure), lcsh:Physics, MONOPOLE STRENGTH
Abstract

Physics letters / B 763, 16 - 19 (2016). doi:10.1016/j.physletb.2016.10.015, Published by North-Holland Publ., Amsterdam

Published
2016

29. Towards the Limits of Existence of Nuclear Structure: Observation and First Spectroscopy of the Isotope K31 by Measuring Its Three-Proton Decay

Author

A. Estrade, Helmut Weick, R. S. Slepnev, G. Marquínez-Durán, Z. Janas, F. Farinon, Yu. A. Litvinov, S. Pietri, Herbert A. Simon, A. V. Gorshkov, R. Knöbel, L. V. Grigorenko, A. M. Sánchez-Benítez, W. Dominik, O. Kiselev, V. B. Dunin, Xurong Xu, C. Nociforo, Branislav Sitar, M. Pomorski, L. Acosta, M. Winkler, A. K. Ordúz, A. A. Ciemny, I. G. Mukha, A. Prochazka, M. Stanoiu, J. A. Dueñas, G. Kaminski, D. A. Kostyleva, J. M. Espino, S. Rymzhanova, C. Scheidenberger, Yukichi Tanaka, Hans Geissel, J. S. Winfield, Peter Strmen, M. Kuich, S. A. Krupko, C. Mazzocchi, M. Pfützner, Enrique Casarejos, Ismael Martel, Imrich Szarka, A. S. Fomichev, V. Chudoba, Mikhail V. Zhukov, and M. Takechi

Subjects
Physics, Isotope, Proton, Proton decay, Nuclear structure, General Physics and Astronomy, Atomic mass unit, 01 natural sciences, 7. Clean energy, 13. Climate action, Excited state, 0103 physical sciences, Atomic physics, 010306 general physics, Spectroscopy, Energy (signal processing)
Abstract

The most remote isotope from the proton dripline (by 4 atomic mass units) has been observed: ^{31}K. It is unbound with respect to three-proton (3p) emission, and its decays have been detected in flight by measuring the trajectories of all decay products using microstrip detectors. The 3p emission processes have been studied by the means of angular correlations of ^{28}S+3p and the respective decay vertices. The energies of the previously unknown ground and excited states of ^{31}K have been determined. This provides its 3p separation energy value S_{3p} of -4.6(2) MeV. Upper half-life limits of 10 ps of the observed ^{31}K states have been derived from distributions of the measured decay vertices.

Published
2019

30. Experimental study of nuclear fission along the thorium isotopic chain: From asymmetric to symmetric fission

Author

Helmut Weick, Laurent Tassan-Got, Håkan T Johansson, T. Gorbinet, L. Grente, J. Vargas, Herbert A. Simon, M. Caamaño, A. Kelic-Heil, S. Pietri, E. Casarejos, B. Laurent, Andreas Martin Heinz, J-F Martin, E. Pellereau, F. Farget, H. Alvarez-Pol, N. Kurz, L. Audouin, B. Jurado, J. Benlliure, Bernd Voss, A. Ebran, A. Prochazka, C. Paradela, J. Taieb, J. L. Rodriguez-Sanchez, Yassid Ayyad, G. Belier, B. Fernández-Domínguez, D. Cortina-Gil, C. Nociforo, A. Chatillon, G. Boutoux, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Physique Nucléaire d'Orsay (IPNO), 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), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Physics, 010308 nuclear & particles physics, Fission, Nuclear Theory, Thorium, chemistry.chemical_element, Coulomb excitation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, chemistry, Nuclear fission, 0103 physical sciences, Nuclear Reactions, Physics::Atomic and Molecular Clusters, Isobaric process, ddc:530, Atomic number, Nuclear Experiment, 010306 general physics, Excitation
Abstract

International audience; The inverse kinematics technique, applied to radioactive beams and combined to the Coulomb excitation method, is a powerful tool to study low-energy fission. A novel experimental setup was developed within the R3B/SOFIA (Reactions with Relativistic Radioactive Beams/Studies On FIssion with Aladin) collaboration to identify in mass and atomic numbers both fission fragments in coincidence. These new data provide elemental, isobaric, and isotonic yields for the fission along the thorium isotopic chain. Results are also compared to previous measurements using either the same reaction mechanism or thermal-neutron induced fission. This latter comparison permits to probe the influence of the excitation energy in the fission process.

Published
2019

31. New spectroscopic information on Tl211,213 : A changing structure beyond the N=126 shell closure

Author

S. Leoni, Hans Geissel, A. Sharma, Robert Hoischen, A. M. Denis Bacelar, A. Bracco, Enrique Casarejos, N. Goel, Matthew Reed, A. Prochazka, D. Bazzacco, S. M. Lenzi, T.P.D. Swan, Imrich Szarka, N. Al-Dahan, Philip M Walker, T. Habermann, A. Gottardo, J. Benlliure, Andrea Corsi, A. Gadea, S. Klupp, E. Gregor, C. Nociforo, Zs. Dombrádi, Alison Bruce, D. Mengoni, Oliver Wieland, Roberto Vicençotto Ribas, A. I. Morales, M. Bunce, Helmut Weick, A. Y. Deo, F. Nowacki, K. Eppinger, C. Domingo-Pardo, A. Algora, M. L. Cortés, E. Sahin, S. Pietri, M. Bowry, J. Alcántara Núñez, H. Schaffner, F. Naqvi, T. Engert, K. Steiger, R. Janik, F. C. L. Crespi, M. Pfützner, J. Gerl, N. Alkhomashi, Maria Doncel, H. J. Wollersheim, W. Prokopowicz, F. Farinon, B. Million, C. A. Ur, Peter Strmen, Y. Ayyad, Davinder Siwal, S. K. Mandal, Roberto Menegazzo, F. Camera, Enrico Maglione, J. J. Valiente-Dobón, P. Boutachkov, Dirk Rudolph, J. Grebosz, P. R. P. Allegro, S. Lunardi, P. H. Regan, G. de Angelis, G. Benzoni, F. Recchia, D. R. Napoli, G. F. Farrelly, Zs. Podolyák, M. Górska, Branislav Sitar, N. Kurz, and I. Kojouharov

Subjects
Physics, Nuclear physics, Fragmentation (mass spectrometry), chemistry, Isotope, 010308 nuclear & particles physics, 0103 physical sciences, Nuclear structure, chemistry.chemical_element, Gamma spectroscopy, Uranium, 010306 general physics, 01 natural sciences
Abstract

The neutron-rich isotopes 211;213Tl, beyond the N = 126 shell-closure, have been studied for the first time in isomer γ-ray decay, exploiting the fragmentation of a primary uranium beam at the FRS-RISING (FRagment Separator-Rare ISotopes INvestigation at GSI) setup at GSI. The observed isomeric states in 211;213Tl show a deviation from the seniority-like scheme of 209Tl. The possible interpretation of the data is discussed on the basis of energy-level systematics and shell-model calculations.

Published
2019

32. Neutron skin and signature of the $N$ = 14 shell gap found from measured proton radii of $^{17-22}$N

Author

A. Evdokimov, J. Atkinson, Hooi Jin Ong, Gaute Hagen, S. Pietri, F. Farinon, Yu. A. Litvinov, S. Bagchi, M. Marta, Branislav Sitar, A. Prochazka, Satbir Kaur, M. Mostazo, M. Takechi, Hans Geissel, Satoru Terashima, I. Dillmann, I. G. Mukha, C. Scheidenberger, R. Kanungo, J. Kurcewicz, R. Janik, G. Guastalla, A. Estrade, Y.K. Tanaka, J. Vargas, D. Cortina-Gil, J. S. Winfield, T. D. Morris, Isao Tanihata, S. R. Stroberg, Helmut Weick, T. Suzuki, Peter Strmen, Junki Tanaka, F. Ameil, Wataru Horiuchi, R. Knöbel, C. Nociforo, Yassid Ayyad, and Geesaman, D. F.

Subjects
Nuclear and High Energy Physics, Proton, Nuclear Theory, Ab initio, Shell (structure), FOS: Physical sciences, 01 natural sciences, Nuclear Theory (nucl-th), Nuclear physics, Root mean square, 0103 physical sciences, ddc:530, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Magic number (physics), Physics, Isotope, 010308 nuclear & particles physics, lcsh:QC1-999, Physics::Accelerator Physics, Halo, lcsh:Physics
Abstract

A thick neutron skin emerges from the first determination of root mean square radii of the proton distributions for $^{17-22}$N from charge changing cross section measurements around 900$A$ MeV at GSI. Neutron halo effects are signaled for $^{22}$N from an increase in the proton and matter radii. The radii suggest an unconventional shell gap at $N$ = 14 arising from the attractive proton-neutron tensor interaction, in good agreement with shell model calculations. $Ab$ $initio$, in-medium similarity re-normalization group, calculations with a state-of-the-art chiral nucleon-nucleon and three-nucleon interaction reproduce well the data approaching the neutron drip-line isotopes but are challenged in explaining the complete isotopic trend of the radii., 18 pages, 3 figures

Published
2019

33. Measurement of proton-distribution radii of neutron-rich nitrogen isotopes

Author

S. Pietri, Satoru Terashima, Alfredo Estradé, R. Knöbel, Hooi Jin Ong, Christoph Scheidenberger, Y.K. Tanaka, Peter Strmen, M. Mostazo, Fabio Farinon, Helmut Weick, Joel Atkinson, R. Janik, Giulia Guastalla, Branislav Sitar, Wataru Horiuchi, Steven Ragnar Stroberg, F. Ameil, Isao Tanihata, Rituparna Kanungo, Iris Dillmann, I. G. Mukha, Hans Geissel, M. Takechi, Yassid Ayyad, Y. Litvinov, J. S. Winfield, Gaute Hagen, C. Nociforo, M. Marta, A. Evdokimov, Toshio Suzuki, J. Kurcewicz, S. Bagchi, J. Vargas, D. Cortina-Gil, A. Prochazka, Junki Tanaka, Satbir Kaur, and T. D. Morris

Subjects
Materials science, Proton, Physics, QC1-999, Nuclear Theory, Shell (structure), Isotopes of nitrogen, Cross section (physics), Distribution (mathematics), Neutron, ddc:530, Halo, Atomic physics, Nuclear Experiment, Line (formation)
Abstract

The European physical journal / Web of Conferences 223, 01003 (2019). doi:10.1051/epjconf/201922301003, Published by EDP Sciences, Les Ulis

Published
2019
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34. Quasi-free neutron and proton knockout reactions from light nuclei in a wide neutron-to-proton asymmetry range

Author

P. J. Woods, Matthias Heil, K. Boretzky, W. N. Catford, A. Henriques, M. Caamaño, Thomas Nilsson, J. Benlliure, P. Velho, Yasuhiro Togano, F. Wamers, I. Syndikus, E. Cravo, H. Alvarez-Pol, Joachim Enders, N. Kurz, O. Sorlin, Rituparna Kanungo, Deniz Savran, C. Nociforo, Mikhail V. Zhukov, L. M. Fraile, Marine Vandebrouck, Björn Jonson, M. Heine, Haik Simon, Roman Gernhäuser, Olof Tengblad, M. Holl, Z. Elekes, M. A. Najafi, Heiko Scheit, Carlos A. Bertulani, Kai Zuber, J. S. Winfield, T. Le Bleis, D. Cortina-Gil, L. Atar, Enrique Casarejos, Joakim Cederkäll, T. Kröll, C. Caesar, G. L. Wilson, G. Ribeiro, A. Kelic-Heil, Christoph Langer, Nasser Kalantar-Nayestanaki, Helmut Weick, Håkan T Johansson, Pavel Golubev, C. Wheldon, Thomas Aumann, Andreas Martin Heinz, Stefanos Paschalis, P. Díaz Fernández, D. M. Rossi, Enrique Nácher, Simon Lindberg, Catherine Rigollet, S. Beceiro-Novo, J. M. Boillos, L. V. Chulkov, Tanja Heftrich, V. Panin, D. Galaviz Redondo, Jorge Machado, Marina Petri, Rene Reifarth, Iris Dillmann, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), R3B, Federal Ministry of Education and Research (Germany), Technische Universität Darmstadt, Helmholtz International Center for FAIR, European Commission, Ministerio de Ciencia e Innovación (España), Ministerio de Economía, Industria y Competitividad (España), Swedish Research Council, National Science Foundation (US), Department of Energy (US), Fundação para a Ciência e a Tecnologia (Portugal), LIBPhys-UNL, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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), and Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Proton, 3313 Tecnología E Ingeniería Mecánicas, media_common.quotation_subject, Nuclear Theory, Aucun, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Asymmetry, Nuclear physics, Momentum, Shell model, 0103 physical sciences, Neutron, ddc:530, 010306 general physics, Nuclear Experiment, Quasi-free scattering, media_common, Physics, Range (particle radiation), 010308 nuclear & particles physics, Scattering, 2207 Física Atómica y Nuclear, lcsh:QC1-999, Inverse kinematics, Isospin, Física nuclear, Spectroscopic factors, Beam (structure), lcsh:Physics
Abstract

7 pags., 4 figs., 2 tabs. -- Open Access funded by Creative Commons Atribution Licence 4.0, The quasi-free scattering reactions C(p,2p) and C(p,pn) have been studied in inverse kinematics at beam energies of 300–400 MeV/u at the RB-LAND setup. The outgoing proton-proton and proton-neutron pairs were detected in coincidence with the reaction fragments in kinematically complete measurements. The efficiency to detect these pairs has been obtained from GEANT4 simulations which were tested using the C(p,2p) and C(p,pn) reactions. Experimental cross sections and momentum distributions have been obtained and compared to DWIA calculations based on eikonal theory. The new results reported here are combined with previously published cross sections for quasi-free scattering from oxygen and nitrogen isotopes and together they enable a systematic study of the reduction of single-particle strength compared to predictions of the shell model over a wide neutron-to-proton asymmetry range. The combined reduction factors show a weak or no dependence on isospin asymmetry, in contrast to the strong dependency reported in nucleon-removal reactions induced by nuclear targets at lower energies. However, the reduction factors for (p,2p) are found to be 'significantly smaller than for (p,pn) reactions for all investigated nuclei., This work was supported by the German Federal Ministry of Education and Research (BMBF projects 05P2015RDFN1 and 05P15WOFNA), through the GSI-TU Darmstadt cooperation agreement, by the State of Hesse through the LOEWE center HIC for FAIR, and the Helmholtz-Gemeinschaft through the graduate school HGS-HIRe. This work was supported by the European Union by means of the European Commission within its Seventh Framework Program (FP7) via ENSAR (Contract No. 262010), and the Spanish CICYT research grants FPA2012-32443, FPA2015-64969-07387, and FPA2015-69640-C2-1-P. This work has supported by the Swedish Research Council under contract number 621-2011-5324. C.A.B. acknowledges support from the U.S. NSF grant No. 1415656 and the U.S. DOE grant No. DE-FG02-08ER41533. Supported by the Portuguese FCT under the project PTDC/FIS/ 103902/2008.

Published
2019

35. Rate capability of a cryogenic stopping cell for uranium projectile fragments produced at 1000 MeV/u

Author

Hans Geissel, R. Knöbel, S. Purushothaman, Julian Bergmann, Peter Dendooven, D. Blum, Christine Hornung, Y.K. Tanaka, M. Pfützner, Helmut Weick, M. Petrick, S. Ayet San Andrés, Ivan Miskun, C. Nociforo, Wayne Lippert, M. Diwisch, Christoph Scheidenberger, F. Heiße, M. Takechi, Moritz P. Reiter, J. Ebert, Ann-Kathrin Rink, Iain Moore, S. Pietri, E. Haettner, Timo Dickel, Florian Greiner, Johannes Lang, F. Amjad, A. Prochazka, C. Jesch, Ilkka Pohjalainen, J. S. Winfield, Wolfgang R. Plaß, Nasser Kalantar-Nayestanaki, X. Xu, Research unit Nuclear & Hadron Physics, and Research unit Medical Physics

Subjects
Nuclear and High Energy Physics, EXTRACTION, Fission, Buffer gas, ION-CATCHER, 01 natural sciences, Space charge, Ion, HEAVY-IONS, Nuclear physics, MOBILITIES, Electric field, Ionization, 0103 physical sciences, Rate capability, ddc:530, SPECTROMETER, 010306 general physics, Nuclear Experiment, Instrumentation, SUPER-FRS, HIGH-PRECISION EXPERIMENTS, ta114, 010308 nuclear & particles physics, Chemistry, Projectile, BEAMS, PERFORMANCE, GAS CELL, Extraction efficiency, Extraction time, Cryogenic gas-filled stopping cell, Atomic physics, Beam (structure)
Abstract

At the Low-Energy Branch (LEB) of the Super-FRS at FAIR, projectile and fission fragments will be produced at relativistic energies, separated in-flight, energy-bunched, slowed down and thermalized in a cryogenic stopping cell (CSC) filled with ultra-pure He gas. The fragments are extracted from the stopping cell using a combination of DC and RF electric fields and gas flow. A prototype CSC for the LEB has been developed and successfully commissioned at the FRS Ion Catcher at GSI. Ionization of He buffer gas atoms during the stopping of energetic ions creates a region of high space charge in the stopping cell. The space charge decreases the extraction efficiency of stopping cells since the high amount of charge distorts the applied DC electric drag fields. Thus the understanding of space charge effects is of great importance to make full use of the high yields at future RIB facilities such as the Super-FRS at FAIR. For this purpose a detailed study of space charge effects in the CSC was performed using experiments and simulations. The dependence of the extraction efficiency, the extraction time and the temporal ion extraction profile on the intensity of the impinging beam and the electric field strength was studied for two different U-238 projectile fragments produced at 1000 MeV/u and separated with the FRS. Good agreement between experiments and simulations was found. (C) 2015 Elsevier B.V. All rights reserved.

Published
2016

36. First direct mass measurements of stored neutron-rich 129,130,131Cd isotopes with FRS-ESR

Author

M. Steck, M. Diwisch, Zygmunt Patyk, F. Bosch, J. Stadlmann, B. Franzke, L. Chen, Sergey Litvinov, C. Scheidenberger, Wolfgang R. Plaß, Toshio Suzuki, R. Knöbel, Bernhard Franczak, C. Kozhuharov, D. Boutin, Akira Ozawa, Milan Matos, Bao-Hua Sun, Marc Hausmann, G. Münzenberg, J. Kurcewicz, Helmut Weick, S. Nakajima, Gabriel Martínez-Pinedo, C. Dimopoulou, P. M. Walker, Takashi Ohtsubo, M. Mazzocco, Meng-Ru Wu, C. Nociforo, F. Nolden, Takayuki Yamaguchi, A. Dolinskii, Hans Geissel, and M. Winkler

Subjects
Nuclear and High Energy Physics, Fission, In-flight separation, Mass models, 01 natural sciences, Isotopes of oxygen, 129,130,131Cd isotopes, Isochronous mass spectrometry, Shell closure at N=82, Storage ring, Isotopes of cadmium, 0103 physical sciences, Isotopes of tin, Neutron, ddc:530, Nuclide, 010306 general physics, Nuclear Experiment, Physics, Isotope, 010308 nuclear & particles physics, Isotopes of chlorine, lcsh:QC1-999, 131Cd isotopes, Atomic physics, lcsh:Physics
Abstract

Physics letters / B 754, 288 - 293 (2016). doi:10.1016/j.physletb.2016.01.039, Published by North-Holland Publ., Amsterdam

Published
2016

37. Evaluation of the counting efficiency of a pcCVD diamond detector irradiated by 62 MeV/nucl. carbon beams

Author

M. Träger, M. Kis, C. Nociforo, S. Schlemme, F. Schirru, J. Enders, R. Visinka, C. Karagiannis, and A. Kratz

Subjects
Materials science, Synthetic diamond, business.industry, Counting efficiency, Detector, chemistry.chemical_element, Diamond, Chemical vapor deposition, engineering.material, law.invention, chemistry, law, engineering, Optoelectronics, Irradiation, business, Instrumentation, Carbon, Radiation hardening, Mathematical Physics
Abstract

It is well known that synthetic diamond exhibits unique properties which make it an attractive material for a broad range of applications in the particle-detection field. In particular, thanks to its radiation hardness and availability in larger sizes, the polycrystalline (pc) diamond sample, grown by chemical vapour deposition (CVD), is especially suitable for online beam-monitoring applications, provided it demonstrates excellent counting performances. The present work reports the counting efficiency of a large 20.0× 20.0× 0.3 mm3 pcCVD diamond detector irradiated by 62 MeV/nucl. carbon beams. The parameter under study was estimated at different particle rates by employing a combination of different detector counters in a sandwich configuration. Results show a counting efficiency of ~ 95% up to 0.7 MHz particle rate. The pcCVD diamond detector under study was selected among other prepared devices by studying their leakage current and photocurrent characteristics under X-ray irradiation.

Published
2020

38. Structure of Be13 studied in proton knockout from B14

Author

Roy Crawford Lemmon, C. Wimmer, U. Datta Pramanik, K. Goebel, I. Syndikus, Nasser Kalantar-Nayestanaki, C. Wheldon, Enrique Nácher, Thomas Aumann, J. S. Winfield, Andreas Martin Heinz, N. Kurz, L. M. Fraile, Hans Geissel, Rene Reifarth, Mikhail V. Zhukov, J. Marganiec, E. Cravo, P. Velho, M. Heine, M. Caamaño, M. Roeder, O. Ershova, Alfredo Estrade, Martin Freer, Daniel Bemmerer, G. L. Wilson, P. J. Woods, S. Pietri, Z. Elekes, G. Ribeiro, Björn Jonson, J. M. Boillos, Joakim Cederkäll, J. Taylor, J. Hagdahl, Herbert A. Simon, Paloma Diaz Fernandez, T. Kroell, Andreas Wagner, Matthias Heil, R. Crespo, A. Ignatov, M. J. G. Borge, K. Riisager, Roman Gernhaeuser, K. Boretzky, A. Movsesyan, Andreas Zilges, Carlos A. Bertulani, A. Hufnagel, H. O. U. Fynbo, A. Kelic-Heil, V. Panin, T. Le Bleis, Christoph Langer, D. Cortina-Gil, L. Atar, E. Casarejos, R. Thies, Jorge Machado, Joachim Enders, Olof Tengblad, Marina Petri, Ralf Plag, J. Benlliure, Deniz Savran, D. M. Rossi, Marielle Chartier, C. Caesar, Y. Aksyutina, Simon Lindberg, Catherine Rigollet, L. V. Chulkov, Daniel Galaviz, M. Holl, O. Sorlin, C. Nociforo, Helmut Weick, Håkan T Johansson, H. Scheit, W. N. Catford, Ángel Perea, Vladimir Avdeichikov, I. Dillmann, Pavel Golubev, F. Farinon, Stefanos Paschalis, H. Alvarez-Pol, R. Kanungo, Marine Vandebrouck, Kai Zuber, M. Labiche, A. Henriques, S. Beceiro-Novo, Thomas Nilsson, F. Wamers, and Tanja Heftrich

Subjects
Physics, Nuclear reaction, Proton, 010308 nuclear & particles physics, Nuclear Theory, Gamma ray, Halo nucleus, 01 natural sciences, Resonance (particle physics), Nuclear physics, Excited state, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

The neutron-unbound isotope Be-13 has been studied in several experiments using different reactions, different projectile energies, and different experimental setups. There is, however, no real consensus in the interpretation of the data, in particular concerning the structure of the low-lying excited states. Gathering new experimental information, which may reveal the Be-13 structure, is a challenge, particularly in light of its bridging role between Be-12, where the N = 8 neutron shell breaks down, and the Borromean halo nucleus Be-14. The purpose of the present study is to investigate the role of bound excited states in the reaction product Be-12 after proton knockout from B-14, by measuring coincidences between Be-12, neutrons, and gamma rays originating from de-excitation of states fed by neutron decay of Be-13. The Be-13 isotopes were produced in proton knockout from a 400 MeV/nucleon B-14 beam impinging on a CH2 target. The Be-12-n relative-energy spectrum d sigma/dE(fn) was obtained from coincidences between Be-12(g.s.) and a neutron, and also as threefold coincidences by adding gamma rays, from the de-excitation of excited states in Be-12. Neutron decay from the first 5/2(+) state in Be-13 to the 2(+) state in Be-12 at 2.11 MeV is confirmed. An energy independence of the proton-knockout mechanism is found from a comparison with data taken with a 35 MeV/nucleon B-14 beam. A low-lying p-wave resonance in Be-13(1/2(-)) is confirmed by comparing proton- and neutron-knockout data from B-14 and Be-14.

Published
2018

39. Deep excursion beyond the proton dripline. I. Argon and chlorine isotope chains

Author

Enrique Casarejos, Luis Acosta, A. V. Gorshkov, O. Kiselev, L. V. Grigorenko, C. Scheidenberger, A. K. Ordúz, A. M. Sánchez-Benítez, W. Dominik, Z. Janas, D. A. Kostyleva, M. Stanoiu, G. Marquínez-Durán, Yu. A. Litvinov, J. A. Dueñas, S. A. Krupko, C. Mazzocchi, Helmut Weick, Peter Strmen, F. Farinon, P. G. Sharov, C. Nociforo, G. Kaminski, M. Kuich, R. Knöbel, M. Takechi, S. Pietri, J. S. Winfield, V. B. Dunin, Yoshiki Tanaka, S. Rymzhanova, Branislav Sitar, M. Pomorski, M. Pfützner, X. Xu, A. A. Ciemny, J. M. Espino, Hans Geissel, Ismael Martel, Imrich Szarka, A. Prochazka, H. Simon, Mikhail V. Zhukov, A. Estrade, R. S. Slepnev, A. S. Fomichev, M. Winkler, I. Mukha, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Helmholtz Association, Helmholtz International Center, Russian Science Foundation, and Polish National Science Center

Subjects
Physics, Argon, Isotope, Proton, 010308 nuclear & particles physics, Proton dripline, Isotopes of chlorine, FOS: Physical sciences, chemistry.chemical_element, 01 natural sciences, Deep excursion, chemistry, Excited state, 0103 physical sciences, Cluster (physics), Chlorine, Isotope chains, Nuclear Experiment (nucl-ex), Atomic physics, 010306 general physics, Ground state, Nuclear Experiment
Abstract

The proton-unbound argon and chlorine isotopes have been studied by measuring trajectories of their decay-in-flight products by using a tracking technique with micro-strip detectors. The proton ($1p$) and two-proton ($2p$) emission processes have been detected in the measured angular correlations "heavy-fragment"+$p$ and "heavy-fragment"+$p$+$p$, respectively. The ground states of the previously unknown isotopes $^{30}$Cl and $^{28}$Cl have been observed for the first time, providing the $1p$-separation energies $S_p$ of $-0.48(2)$ and $-1.60(8)$ MeV, respectively. The relevant systematics of $1p$ and $2p$ separations energies have been studied theoretically in the core+$p$ and core+$p$+$p$ cluster models. The first-time observed excited states of $^{31}$Ar allow to infer the $2p$-separation energy $S_{2p}$ of 6(34) keV for its ground state. The first-time observed state in $^{29}$Ar with $S_{2p} = -5.50(18)$ MeV can be identified either as a ground or an excited state according to different systematics., 13 pages, 14 figures. Name changed, some affiliations changed and figures corrections added

Published
2018

40. Strong neutron pairing in core+4n nuclei

Author

S. Beceiro-Novo, R. Thies, Jorge Machado, Andreas Martin Heinz, Tanja Heftrich, L. M. Fraile, A. Estrade, Marina Petri, T. Le Bleis, D. Cortina-Gil, L. Atar, T. Kröll, A. Knyazev, M. A. Najafi, G. L. Wilson, D. Rossi, Kai Zuber, A. Movsesyan, Z. Elekes, Simon Lindberg, I. Syndikus, P. Díaz Fernández, K. Göbel, Catherine Rigollet, Ángel Perea, R. Crespo, F. Farinon, J. Kahlbow, V. Volkov, M. Caamaño, W. N. Catford, A. Ignatov, S. Pietri, Carlos A. Bertulani, V. Panin, C. Langer, A. Kelic-Heil, O. Sorlin, Stefanos Paschalis, J. M. Boillos, Enrique Casarejos, J. Hagdahl, Iris Dillmann, M Vandebrouck, O. Ershova, K. Boretzky, A. Henriques, Roy Crawford Lemmon, J. S. Winfield, J. Benlliure, M. Labiche, Vladimir Avdeichikov, Enrique Nácher, H. Weick, Thomas Nilsson, F. Wamers, Rituparna Kanungo, M. Holl, C. Caesar, P. Velho, Håkan T Johansson, G. Ribeiro, Pavel Golubev, F. M. Marqués, M. Heine, Andreas Zilges, Hans Geissel, J. Enders, D. Galaviz, Daniel Bemmerer, Deniz Savran, Marielle Chartier, María José García Borge, Haik Simon, M. Freer, J. Taylor, Nasser Kalantar-Nayestanaki, Olof Tengblad, C. Wheldon, C. Nociforo, A. Revel, H. Alvarez-Pol, Joakim Cederkäll, Thomas Aumann, Rene Reifarth, L. Chulkov, J. Marganiec, Mikhail V. Zhukov, D. Yakorev, Björn Jonson, M. Röder, Philip Woods, R. Plag, U. Datta Pramanik, Andreas Wagner, R. Gernhäuser, E. Cravo, Y. Togano, H. Scheit, N. Kurz, M. Heil, Grand Accélérateur National d'Ions Lourds ( GANIL ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de physique corpusculaire de Caen ( LPCC ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ) -Normandie Université ( NU ) -Ecole 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 de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien ( IPHC ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Strasbourg ( UNISTRA ), R3B, Technische Universität Darmstadt, Federal Ministry of Education and Research (Germany), National Science Foundation (US), Department of Energy (US), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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 de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and 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)

Subjects
Physics, Valence (chemistry), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Aucun, General Physics and Astronomy, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Molecular physics, Pairing, 0103 physical sciences, Neutron, Física nuclear, Nuclear Experiment (nucl-ex), [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, Nucleon, Nuclear Experiment, R3B radioactive beams nuclear structure neutron-rich Coulomb dissociation
Abstract

6 pags., 4 figs., The emission of neutron pairs from the neutron-rich N = 12 isotones C-18 and O-20 has been studied by high-energy nucleon knockout from N-19 and O-21 secondary beams, populating unbound states of the two isotones up to 15 MeV above their two-neutron emission thresholds. The analysis of triple fragment-n-n correlations shows that the decay N-19(-1p)18C*-> C-16 + n + n is clearly dominated by direct pair emission. The two- neutron correlation strength, the largest ever observed, suggests the predominance of a C-14 core surrounded by four valence neutrons arranged in strongly correlated pairs. On the other hand, a significant competition of a sequential branch is found in the decay O-21(-1n)O-20*-> O-18 + n + n, attributed to its formation through the knockout of a deeply bound neutron that breaks the O-16 core and reduces the number of pairs., This work was supported by the German Federal Ministry for Education and Research (BMBF Project No. 05P15RDFN1), and through the GSI-TU Darmstadt cooperation agreement. C. A. Bertulani acknowledges support by U.S. Department of Energy Grant No. DE-FG02-08ER41533 and U.S. National Science Foundation Grant No. 1415656.

Published
2018

41. Comparison of electromagnetic and nuclear dissociation of Ne-17

Author

H. O. U. Fynbo, Deniz Savran, F. Aksouh, Christoph Langer, D. Cortina-Gil, J. Hoffman, Mattias Lantz, Michael Heil, O. Kiselev, W. Ott, Achim Richter, Thomas Aumann, K. Riisager, R. Kulessa, Björn Jonson, C. Lehr, L. M. Fraile, Dieter H. H. Hoffmann, Ángel Perea, J. Marganiec, Carlos A. Bertulani, C. Nociforo, Marielle Chartier, C. Karagiannis, Thomas Nilsson, Stefan Typel, V. Panin, F. Wamers, Y. Aksyutina, Hans Geissel, K. Sümmerer, Ralf Plag, H. Emling, Stefanos Paschalis, S. Beceiro-Novo, N. Kurz, O. Ershova, K. Mahata, Roy Crawford Lemmon, C. Wimmer, J. V. Kratz, D. Galaviz, A. Chatillon, Herbert A. Simon, T. Le Bleis, Olof Tengblad, Helmut Weick, Håkan T Johansson, H. Alvarez-Pol, C. Muntz, Michael Wiescher, Yu. A. Litvinov, D. M. Rossi, C. Rodriguez-Tajes, Joachim Stroth, M. J. G. Borge, G. Schrieder, K. Boretzky, Rene Reifarth, L. Chulkov, Department of Energy (US), National Science Foundation (US), German Research Foundation, Federal Ministry of Education and Research (Germany), European Money Markets Institute, Helmholtz International Center for FAIR, Technische Universität Darmstadt, and Ministerio de Economía y Competitividad (España)

Subjects
Physics, COLLISIONS, Internal energy, 010308 nuclear & particles physics, 01 natural sciences, 7. Clean energy, STATE, Dissociation (chemistry), Coincidence, CAPTURE, Reaction rate, medicine.anatomical_structure, Fragmentation (mass spectrometry), 0103 physical sciences, medicine, Halo, Atomic physics, 010306 general physics, Ground state, DECAY, Nucleus
Abstract

8 pags., 10 figs., 3 tabs., The Borromean drip-line nucleus Ne-17 has been suggested to possess a two-proton halo structure in its ground state. In the astrophysical rp-process, where the two-proton capture reaction O-15(2p,gamma) Ne-17 plays an important role, the calculated reaction rate differs by several orders of magnitude between different theoretical approaches. To add to the understanding of the Ne-17 structure we have studied nuclear and electromagnetic dissociation. A 500 MeV/u Ne-17 beam was directed toward lead, carbon, and polyethylene targets. Oxygen isotopes in the final state were measured in coincidence with one or two protons. Different reaction branches in the dissociation of Ne-17 were disentangled. The relative populations of s and d states in F-16 were determined for light and heavy targets. The differential cross section for electromagnetic dissociation (EMD) shows a continuous internal energy spectrum in the three-body system O-15 + 2p. The Ne-17 EMD data were compared to current theoretical models. None of them, however, yields satisfactory agreement with the experimental data presented here. These new data may facilitate future development of adequate models for description of the fragmentation process., This project is supported by NAVI, GSI-TU Darmstadt cooperation, HIC for FAIR, EMMI, and BMBF and from DFG through Grant No. SFB1245 and from BMBF via Project No. 05P15RDFN1, and from the Spanish Ministry by research grant FPA2015-64969-P. C.A.B. acknowledges support by the US DOE Grant No. DE-FG02-08ER41533 and the US NSF Grant No. 1415656.

Published
2018

42. Spectroscopy of excited states of unbound nuclei Ar30 and Cl29

Author

Ismael Martel, Imrich Szarka, T. A. Golubkova, Z. Janas, A. M. Sánchez-Benítez, W. Dominik, M. Takechi, Yu. A. Litvinov, Yoshiki Tanaka, R. Knöbel, V. B. Dunin, S. Pietri, C. Nociforo, M. Pfützner, A. Estrade, R. S. Slepnev, L. V. Grigorenko, Luis Acosta, I. Mukha, A. A. Ciemny, F. Farinon, O. Kiselev, C. Scheidenberger, G. Marquínez-Durán, X. Xu, J. Duénas-Díaz, Branislav Sitar, M. Pomorski, M. Winkler, G. Kaminski, M. Kuich, A. K. Ordúz, S. Rymzhanova, M. Stanoiu, P. G. Sharov, A. Prochazka, J. S. Winfield, Helmut Weick, J. M. Espino, H. Simon, Hans Geissel, S. A. Krupko, C. Mazzocchi, A. V. Gorshkov, A. S. Fomichev, Peter Strmen, Enrique Casarejos, and V. Chudoba

Subjects
Joint research, Physics, 010308 nuclear & particles physics, 0103 physical sciences, Library science, Christian ministry, 010306 general physics, 01 natural sciences
Abstract

This work was supported in part by the Helmholtz International Center for FAIR (HIC for FAIR), the Helmholtz Association (grant IK-RU-002), the Russian Ministry of Education and Science (grant No. NSh- 932.2014.2), the Russian Science Foundation (grant No. 17-12-01367), the Polish National Science Center (Contract No. UMO-2011/01/B/ST2/01943), the Polish Ministry of Science and Higher Education (Grant No. 0079/DIA/2014/43,Grant Diamentowy), the Helmholtz- CAS Joint Research Group (grant HCJRG-108), the FPA2009-08848 contract (MICINN, Spain), the Justus- Liebig-Universit¨at Giesen (JLU) and GSI under the JLUGSI strategic Helmholtz partnership agreement. This article is a part of PhD thesis of X.-D. Xu. The authors acknowledge the help of D. Kostyleva in the preparation of the manuscript.

Published
2018

43. Quasifree ( p,pN ) scattering of light neutron-rich nuclei near N=14

Author

Roy Crawford Lemmon, M. Röder, Rituparna Kanungo, P. Cabanelas, M. Heil, S. Pietri, Hans Geissel, E. Y. Nikolskii, A. Movsesyan, J. Marganiec, O. Ershova, J. Enders, N. Kurz, V. Volkov, K. Boretzky, Iris Dillmann, Stefanos Paschalis, H. Scheit, F. Farinon, A. Estrade, Vladimir Avdeichikov, R. Plag, G. L. Wilson, A. Najafi, L. M. Fraile, V. Panin, A. M. Moro, D. Jurčiukonis, Simon Lindberg, Catherine Rigollet, Kai Zuber, U. Datta Pramanik, A. Henriques, J. Benlliure, F. Wamers, D. Yakorev, Carlos A. Bertulani, María José García Borge, J. S. Winfield, C. Langer, Andreas Zilges, I. Syndikus, A. Kelic-Heil, A. Deltuva, Thomas Nilsson, T. Le Bleis, M. Heine, G. Ribeiro, E. Cravo, D. Cortina-Gil, L. Atar, Nasser Kalantar-Nayestanaki, Mikhail V. Zhukov, Daniel Bemmerer, C. Wheldon, Marine Vandebrouck, D. Galaviz, Thomas Aumann, Y. Togano, Andreas Martin Heinz, O. Sorlin, Björn Jonson, M. Holl, T. Kröll, Andreas Wagner, Joakim Cederkäll, S. Beceiro-Novo, Ángel Perea, Enrique Nácher, Z. Elekes, H. Weick, B. Fernández-Domínguez, Philip Woods, Håkan T Johansson, K. Göbel, R. Gernhäuser, B. Pietras, Deniz Savran, Pavel Golubev, Haik Simon, M. Freer, Olof Tengblad, Rene Reifarth, Tanja Heftrich, C. Nociforo, W. N. Catford, D. Rossi, H. Alvarez-Pol, A. Ignatov, L. Chulkov, C. Caesar, J. Taylor, P. Velho, R. Crespo, A. Knyazev, R. Thies, Jorge Machado, Marina Petri, J. M. Boillos, J. Hagdahl, A. Hufnagel, M. Labiche, P. Díaz Fernández, Marielle Chartier, M. Caamaño, and Enrique Casarejos

Subjects
Physics, Proton, Inverse kinematics, 010308 nuclear & particles physics, Scattering, Nuclear Theory, Inverse, 01 natural sciences, Light scattering, Nuclear physics, Momentum, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, Beam (structure)
Abstract

Background: For many years, quasifree scattering reactions in direct kinematics have been extensively used to study the structure of stable nuclei, demonstrating the potential of this approach. The (RB)-B-3 collaboration has performed a pilot experiment to study quasifree scattering reactions in inverse kinematics for a stable C-12 beam. The results from that experiment constitute the first quasifree scattering results in inverse and complete kinematics. This technique has lately been extended to exotic beams to investigate the evolution of shell structure, which has attracted much interest due to changes in shell structure if the number of protons or neutrons is varied. Purpose: In this work we investigate for the first time the quasifree scattering reactions (p, pn) and (p, 2p) simultaneously for the same projectile in inverse and complete kinematics for radioactive beams with the aim to study the evolution of single-particle properties from N = 14 to N = 15. Method: The structure of the projectiles O-23, O-22, and N-21 has been studied simultaneously via (p, pn) and (p, 2p) quasifree knockout reactions in complete inverse kinematics, allowing the investigation of proton and neutron structure at the same time. The experimental data were collected at the (RB)-B-3-LAND setup at GSI at beam energies of around 400 MeV/u. Two key observables have been studied to shed light on the structure of those nuclei: the inclusive cross sections and the corresponding momentum distributions. Conclusions: The knockout reactions (p, pn) and (p, 2p) with radioactive beams in inverse kinematics have provided important and complementary information for the study of shell evolution and structure. For the (p, pn) channels, indications of a change in the structure of these nuclei moving from N = 14 to N = 15 have been observed, i.e., from the 0d(5/2) shell to the 1s(1/2). This supports previous observations of a subshell closure at N = 14 for neutron-rich oxygen isotopes and its weakening for the nitrogen isotopes.

Published
2018

44. Quasifree ( p , 2p ) Reactions on Oxygen Isotopes: Observation of Isospin Independence of the Reduced Single-Particle Strength

Author

Rene Reifarth, J. Kahlbow, E. Y. Nikolskii, R. Thies, Jorge Machado, M. Heine, A. Estrade, Marina Petri, G. Ribeiro, J. Taylor, Daniel Bemmerer, M. A. Najafi, Haik Simon, M. Freer, Olof Tengblad, Enrique Casarejos, H. Alvarez-Pol, Kai Zuber, F. Farinon, C. Nociforo, D. Rossi, Nasser Kalantar-Nayestanaki, C. Wheldon, Thomas Aumann, K. Boretzky, L. Chulkov, Andreas Martin Heinz, C. Caesar, Vladimir Avdeichikov, Tanja Heftrich, J. M. Boillos, J. Hagdahl, V. Panin, D. Galaviz Redondo, Ángel Perea, T. Kröll, Joakim Cederkäll, A. Ignatov, Carlos A. Bertulani, N. Kurz, A. Hufnagel, M. Labiche, S. Pietri, V. Volkov, P. Díaz Fernández, Mikhail V. Zhukov, G. L. Wilson, Simon Lindberg, Carlo Barbieri, I. Syndikus, J. Benlliure, F. Wamers, M. Heil, Marine Vandebrouck, Catherine Rigollet, M. Caamaño, Enrique Nácher, H. Weick, S. Beceiro-Novo, C. Langer, O. Ershova, A. Kelic-Heil, P. Velho, A. Henriques, J. S. Winfield, Thomas Nilsson, A. Knyazev, E. Cravo, Håkan T Johansson, R. Crespo, María José García Borge, Pavel Golubev, O. Sorlin, H. Scheit, Marielle Chartier, M. Holl, Deniz Savran, I. Dillmann, Stefanos Paschalis, D. Yakorev, Y. Togano, J. Marganiec-Gałązka, T. Le Bleis, D. Cortina-Gil, Rituparna Kanungo, Hans Geissel, L. Atar, A. Movsesyan, L. M. Fraile, Björn Jonson, Philip Woods, Andreas Wagner, R. Gernhäuser, Andreas Zilges, J. Enders, R. Lemmon, M. Röder, Z. Elekes, K. Göbel, R. Plag, and W. N. Catford

Subjects
Physics, Range (particle radiation), 010308 nuclear & particles physics, Eikonal equation, media_common.quotation_subject, Nuclear Theory, Ab initio, General Physics and Astronomy, chemistry.chemical_element, 7. Clean energy, 01 natural sciences, Asymmetry, Oxygen, Isotopes of oxygen, Nuclear physics, chemistry, Isospin, 0103 physical sciences, Particle, Nuclear Experiment, 010306 general physics, media_common
Abstract

Quasifree one-proton knockout reactions have been employed in inverse kinematics for a systematic study of the structure of stable and exotic oxygen isotopes at the R3B/LAND setup with incident beam energies in the range of 300-450 MeV/u. The oxygen isotopic chain offers a large variation of separation energies that allows for a quantitative understanding of single-particle strength with changing isospin asymmetry. Quasifree knockout reactions provide a complementary approach to intermediate-energy one-nucleon removal reactions. Inclusive cross sections for quasifree knockout reactions of the type OA(p,2p)NA-1 have been determined and compared to calculations based on the eikonal reaction theory. The reduction factors for the single-particle strength with respect to the independent-particle model were obtained and compared to state-of-the-art ab initio predictions. The results do not show any significant dependence on proton-neutron asymmetry.

Published
2018

45. Deep excursion beyond the proton dripline. II. Toward the limits of existence of nuclear structure

Author

Enrique Casarejos, Yasumoto Tanaka, V. Chudoba, M. Stanoiu, Luis Acosta, Yu. A. Litvinov, S. Pietri, R. Knöbel, Ismael Martel, Imrich Szarka, M. Winkler, A. K. Ordúz, A. A. Ciemny, Z. Janas, L. V. Grigorenko, S. Rymzhanova, E. Yu. Nikolskii, D. A. Kostyleva, A. Prochazka, H. Simon, A. S. Fomichev, Peter Strmen, A. M. Sánchez-Benítez, W. Dominik, Helmut Weick, M. Pfützner, A. V. Gorshkov, G. Marquínez-Durán, J. M. Espino, S. A. Krupko, O. Kiselev, Hans Geissel, C. Scheidenberger, C. Mazzocchi, C. Nociforo, I. Mukha, X. Xu, G. Kaminski, M. Kuich, F. Farinon, P. G. Sharov, J. S. Winfield, M. Takechi, V. B. Dunin, Mikhail V. Zhukov, A. Estrade, R. S. Slepnev, J. A. Dueñas, Branislav Sitar, M. Pomorski, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Helmholtz Association. Alemania, Russian Science Foundation, Polish National Science Center, Helmholtz- CAS Joint Research Group. Alemania, Ministerio de Educación y Ciencia (MEC). España, and Ministry of Education, Youth and Sports. Czech Republic

Subjects
Physics, Argon, Proton, Spectrometer, 010308 nuclear & particles physics, Gamma ray, Nuclear structure, Isotopes of chlorine, Isotopes of argon, chemistry.chemical_element, FOS: Physical sciences, 01 natural sciences, Nuclear physics, chemistry, 0103 physical sciences, Cluster (physics), Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment
Abstract

Prospects of experimental studies of argon and chlorine isotopes located far beyond the proton dripline are studied by using systematics and cluster models. The deviations from the widespread systematics observed in $^{28,29}$Cl and $^{29,30}$Ar have been theoretically substantiated, and analogous deviations predicted for the lighter chlorine and argon isotopes. The limits of nuclear structure existence are predicted for Ar and Cl isotopic chains, with $^{26}$Ar and $^{25}$Cl found to be the lightest sufficiently long-living nuclear systems. By simultaneous measurements of protons and $\gamma$-rays following decays of such systems as well as their $\beta$-delayed emission, an interesting synergy effect may be achieved, which is demonstrated by the example of $^{30}$Cl and $^{31}$Ar ground state studies. Such synergy effect may be provided by the new EXPERT setup (EXotic Particle Emission and Radioactivity by Tracking), being operated inside the fragment separator and spectrometer facility at GSI, Darmstadt., Comment: 10 pages, 9 figures. Chapter added, language and some figures corrected

Published
2018

46. A Sample of the Results of the First SOFIA Experiment

Author

Herbert A. Simon, Yassid Ayyad, Enrique Casarejos, D. M. Rossi, J. Benlliure, B. Fernández-Domínguez, D. Cortina-Gil, N. Kurz, Bernd Voss, A. Ebran, M. Caamaño, A. Chatillon, G. Boutoux, B. Laurent, C. Paradela, L. Audouin, H. Alvarez-Pol, A. Prochazka, T. Gorbinet, J. Taieb, J. S. Winfield, J. L. Rodriguez-Sanchez, Beatriz Jurado, K.-H. Schmidt, J. Vargas, G. Belier, A. Kelic-Heil, S. Pietri, C. Nociforo, Helmut Weick, E. Pellereau, Andreas Martin Heinz, J. F. Martin, and L. Tassan-Got

Subjects
Physics, Range (particle radiation), Cold fission, Cluster decay, Fission, Nuclear Theory, Isotopic yields, Actinide, Physics and Astronomy(all), Effective nuclear charge, Coincidence, Nuclear physics, Relativistic secondary radioactive beams, Inverse kinematics, Nuclear Experiment, Excitation, Electromagnetic-induced fission
Abstract

The first SOFIA experiment (Studies On FIssion with Aladin) was performed in August 2012 at GSI. The fission of several neutron-deficient actinides and pre-actinides was induced in flight at 700 A MeV by electromagnetic excitation. The use of inverse kinematics provides both high detection and high geometrical efficiency. The complete identification of both fission fragments in coincidence (nuclear charge and mass) was obtained over a broad range of fissioning nuclei. After a short introduction and descrip- tion of the experimental setup, the quality of the charge and mass separation is presented, followed by some results concerning the Coulex-induced fission of 234U and 235U.

Published
2015
Full Text
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47. Effective proton-neutron interaction near the drip line from unbound states in F25,26

Author

R. Crespo, Hans Geissel, Ralf Plag, J. Benlliure, Jason D. Holt, H. Hergert, Marine Vandebrouck, Christoph Langer, J. M. Boillos, Z. Elekes, J. Hagdahl, T. Kröll, J. Taylor, J. S. Winfield, A. Kelic-Heil, C. Caesar, Björn Jonson, Rene Reifarth, Roman Gernhäuser, A. Ignatov, D. M. Rossi, D. Galaviz, Joachim Enders, L. Chulkov, Deniz Savran, Ángel Perea, A. Lepailleur, F. Farinon, M. Heine, M. A. Najafi, Mikhail V. Zhukov, Nasser Kalantar-Nayestanaki, Andreas Wagner, T. Le Bleis, J. Kahlbow, Daniel Bemmerer, R. Kanungo, P. Velho, E. Y. Nikolskii, O. Sorlin, C. Wheldon, Thomas Aumann, M. Caamaño, D. Cortina-Gil, Stefanos Paschalis, Andreas Martin Heinz, L. Atar, Iris Dillmann, C. Nociforo, A. Henriques, R. Thies, Jorge Machado, O. Ershova, V. Panin, Marina Petri, Joakim Cederkäll, M. Holl, E. Cravo, Thomas Nilsson, A. Estrade, V. Volkov, W. N. Catford, Olof Tengblad, Vladimir Avdeichikov, Martin Freer, Marielle Chartier, F. Wamers, Simon Lindberg, M. J. G. Borge, Kai Zuber, Kathrin Göbel, Enrique Nácher, M. Röder, U. Datta Pramanik, Catherine Rigollet, H. Alvarez-Pol, Julien Gibelin, K. Boretzky, Yasuhiro Togano, M. Heil, I. Syndikus, L. M. Fraile, P. Díaz Fernández, A. Knyazev, S. R. Stroberg, S. Beceiro-Novo, Achim Schwenk, Tanja Heftrich, A. Movsesyan, D. Yakorev, A. Hufnagel, J. Marganiec, Helmut Weick, Håkan T Johansson, H. Scheit, Pavel Golubev, F. M. Marqués, Andreas Zilges, M. Labiche, G. L. Wilson, F. de Oliveira Santos, Carlos A. Bertulani, G. Ribeiro, P. J. Woods, S. Pietri, Enrique Casarejos, N. Kurz, Scott Bogner, Herbert A. Simon, and Roy Crawford Lemmon

Subjects
Physics, 010308 nuclear & particles physics, Binding energy, Ab initio, Resonance, 7. Clean energy, 01 natural sciences, Atomic mass, 0103 physical sciences, Bound state, Nuclear force, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Multiplet
Abstract

Background: Odd-odd nuclei, around doubly closed shells, have been extensively used to study proton-neutron interactions. However, the evolution of these interactions as a function of the binding energy, ultimately when nuclei become unbound, is poorly known. The F-26 nucleus, composed of a deeply bound pi 0d(5/2) proton and an unbound v0d(3/2) neutron on top of an O-24 core, is particularly adapted for this purpose. The coupling of this proton and neutron results in a J(pi) = 1(1)(+) - 4(1)(+) multiplet, whose energies must be determined to study the influence of the proximity of the continuum on the corresponding proton-neutron interaction. The J(pi) = 1(1)(+), 2(1)(+), 4(1)(+) bound states have been determined, and only a clear identification of the J(pi) = 3(1)(+) is missing. Purpose: We wish to complete the study of the J(pi) = 1(1)(+) - 4(1)(+) multiplet in F-26, by studying the energy and width of the J(pi) = 3(1)(+) unbound state. The method was first validated by the study of unbound states in F-25, for which resonances were already observed in a previous experiment. Method: Radioactive beams of Ne-26 and Ne-27, produced at about 440AMeV by the fragment separator at the GSI facility were used to populate unbound states in F-25 and F-26 via one-proton knockout reactions on a CH2 target, located at the object focal point of the (RB)-B-3/LAND setup. The detection of emitted. rays and neutrons, added to the reconstruction of the momentum vector of the A - 1 nuclei, allowed the determination of the energy of three unbound states in F-25 and two in F-26. Results: Based on its width and decay properties, the first unbound state in F-25, at the relative energy of 49(9) keV, is proposed to be a J(pi) = 1/ 2(-) arising from a p1/2 proton- hole state. In F-26, the first resonance at 323(33) keV is proposed to be the J(pi) = 3(1)(+) member of the J(pi) = 1(1)(+) - 4(1)(+) multiplet. Energies of observed states in F-25,F-26 have been compared to calculations using the independent-particle shell model, a phenomenological shell model, and the ab initio valence-space in-medium similarity renormalization group method. Conclusions: The deduced effective proton- neutron interaction is weakened by about 30-40% in comparison to the models, pointing to the need for implementing the role of the continuum in theoretical descriptions or to a wrong determination of the atomic mass of F-26.

Published
2017

48. Nuclear-matter radius studies from Ni58(α,α) experiments at the GSI Experimental Storage Ring with the EXL facility

Author

Hans Geissel, Tatsuya Furuno, Santosh Roy, C. Dimopoulou, U. Popp, J. S. Winfield, Takayuki Yamaguchi, Iris Dillmann, F. Nolden, M. Csatlós, Yu. A. Litvinov, Peter Egelhof, M. Kuilman, M.N. Harakeh, D. Nagae, B. Streicher, P. J. Woods, Th. Kroell, M. Steck, H. Kollmus, S. Boenig, L. Stuhl, O. Kiselev, M. A. Najafi, Juzo Zenihiro, M. Thuerauf, Tomohiro Uesaka, C. Scheidenberger, C. Nociforo, Nasser Kalantar-Nayestanaki, Thomas Aumann, K. Yue, A.-L. Hartig, Catherine Rigollet, S. Ilieva, C. Kozhuharov, Helmut Weick, M. Mahjour-Shafiei, S. Bagchi, J. C. Zamora, Danyal Winters, V. K. Eremin, Sergey Litvinov, A. Krasznahorkay, M. von Schmid, Manfred Mutterer, and Roman Gernhaeuser

Subjects
Nuclear reaction, Physics, Elastic scattering, 010308 nuclear & particles physics, chemistry.chemical_element, Radius, Nuclear matter, 01 natural sciences, Eikonal approximation, Ion, Nuclear physics, chemistry, 0103 physical sciences, 010306 general physics, Helium, Storage ring
Abstract

A novel method for measuring nuclear reactions in inverse kinematics with stored ion beams was successfully used to extract the nuclear-matter radius of $^{58}\mathrm{Ni}$. The experiment was performed at the experimental heavy-ion storage ring at the GSI facility using a stored $^{58}\mathrm{Ni}$ beam at energies of 100 and 150 MeV/u and an internal helium gas-jet target. Elastically scattered $\ensuremath{\alpha}$-recoils at low momentum transfers were measured with an in-ring detector system compatible with ultrahigh vacuum. Experimental angular distributions were fitted using density-dependent optical model potentials within the eikonal approximation. This permitted the extraction of the point-matter root-mean-square radius of $^{58}\mathrm{Ni}$ with an average value of 3.70(7) fm. Results from this work are in good agreement with several experiments performed in the past in normal kinematics. This pioneering experiment demonstrates a major breakthrough towards future investigations with far-from-stability stored beams using the present technique.

Published
2017

49. Ground-state configuration of neutron-rich Al-35 via Coulomb breakup

Author

Reiner Kruecken, Heiko Scheit, T. Le Bleis, V. Panin, M. V. Ricciardi, Andreas Wagner, Helmut Weick, D. Cortina-Gil, Håkan T Johansson, Nasser Kalantar-Nayestanaki, J. Taylor, Thomas Nilsson, Yasuhiro Togano, W. N. Catford, Hans Geissel, Thomas Aumann, C. Scheidenberger, T. Kroell, F. Wamers, P. Díaz Fernández, D. M. Rossi, O. Ershova, G. Münzenberg, S. Chakraborty, Björn Jonson, M. A. Najafi, Ralf Plag, L. M. Fraile, Marielle Chartier, Stefan Typel, S. Beceiro-Novo, J. Marganiec, C. Nociforo, Rene Reifarth, Ushasi Datta, K. Boretzky, Yutaka Utsuno, G. de Angelis, Yvonne Leifels, B. V. Carlson, C. Langer, Anisur Rahaman, Herbert A. Simon, H. Emling, Catherine Rigollet, D. González-Díaz, C. Caesar, J. S. Winfield, and Research unit Nuclear & Hadron Physics

Subjects
Physics, ISLAND, IONS, COLLISIONS, Valence (chemistry), NUCLEI, Ion, N=20 SHELL CLOSURE, Atomic orbital, Excited state, EXCITATION, Coulomb, ISOTOPES, Neutron, INVERSION, Atomic physics, Nucleon, Ground state, EMISSION, MASS MEASUREMENTS
Abstract

The ground-state configuration of Al-35 has been studied via Coulomb dissociation (CD) using the LAND-FRS setup (GSI, Darmstadt) at a relativistic energy of similar to 403 MeV/nucleon. The measured inclusive differential CD cross section for Al-35, integrated up to 5.0 MeV relative energy between the Al-34 core and the neutron using a Pb target, is 78(13) mb. The exclusive measured CD cross section that populates various excited states of 34Al is 29(7) mb. The differential CD cross section of Al-35 -> Al-34 + n has been interpreted in the light of a direct breakup model, and it suggests that the possible ground-state spin and parity of Al-35 could be, tentatively, 1/2+ or 3/2(+) or 5/2(+). The valence neutrons, in the ground state of Al-35, may occupy a combination of either l = 3,0 or l = 1,2 orbitals coupled with the Al-34 core in the ground and isomeric state(s), respectively. This hints of a particle-hole configuration of the neutron across the magic shell gaps at N = 20,28 which suggests narrowing the magic shell gap. If the 5/2+ is the ground-state spin-parity of Al-35 as suggested in the literature, then the major ground-state configuration of Al-35 is a combination of Al-34(g. s.; 4(-)) circle times upsilon(p3/2) and Al-34(isomer; 1(+)) circle times upsilon(d3/2) states. The result from this experiment has been compared with that from a previous knockout measurement and a calculation using the SDPF-M interaction.

Published
2017

50. β -decay half-lives and β -delayed neutron emission probabilities for several isotopes of Au, Hg, Tl, Pb, and Bi, beyond N=126

Author

Yu. A. Litvinov, I. Dillmann, K. Steiger, Karl Smith, Hans Geissel, G. Cortes, Carlos Guerrero, E. Wilson, J. L. Tain, A. R. García, Roman Gernhäuser, E. Sokol, H. Schaffner, N. Kurz, A. Evdokimov, C. Domingo-Pardo, Helmut Weick, S. Pietri, J. Benlliure, M. Marta, D. Cano-Ott, L. Maier, R. Caballero-Folch, J. Agramunt, F. Calviño, J. Kurcewicz, F. Montes, A. Algora, M. Bowry, T. Martinez, A. Prochazka, A. V. Yeremin, C. Paradela, J. Marganiec, F. Ameil, M. B. Gómez-Hornillos, D. Galaviz, R. Knöbel, Zs. Podolyák, Stephen Rice, B. Rubio, C. Nociforo, Bao-Hua Sun, I. Kojouharov, D. Testov, Yassid Ayyad, C. Scheidenberger, R. Wood, D. R. Napoli, Philip Woods, Matthias Heil, Ivan Mukha, W. Gelletly, F. Farinon, A. Riego, M. Takechi, C. Hinke, A. Estrade, J. S. Winfield, Thomas Faestermann, and Thomas Davinson

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Branching fraction, 01 natural sciences, 7. Clean energy, Ion, 0103 physical sciences, Neutron detection, r-process, Neutron, Atomic physics, 010306 general physics, s-process, Delayed neutron
Abstract

Background: Previous measurements of Beta-delayed neutron emitters comprise around 230 nuclei, spanning from the 8He up to 150La. Apart from 210Tl, with a minuscule branching ratio of 0.07%, no other neutron emitter is measured yet beyond A = 150. Therefore new data are needed, particularly in the heavy mass region around N=126, in order to guide theoretical models and to understand the formation of the third r-process peak at A 195. Purpose: To measure both, Beta-decay half-lives and neutron branching ratios of several neutron-rich Au, Hg, Tl, Pb and Bi isotopes beyond N = 126. Method: Ions of interest are produced by fragmentation of a 238U beam, selected and identifed via the GSI-FRS fragment separator. A stack of segmented silicon detectors (SIMBA) is used to measure ion-implants and -decays. An array of 30 3He tubes embedded in a polyethylene matrix (BELEN) is used to detect neutrons with high efficiency and selectivity. A self-triggered digital system is employed to acquire data and to enable time-correlations. The latter are analyzed with an analytical model and results for the half-lives and neutron-branching ratios are derived using the binned Maximum-Likelihood method. Results: Twenty new Beta-decay half-lives are reported for 204

Published
2017

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