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92 results on '"Jentschel , M."'

1. Measurement of relative isotopic yield distribution of even-even fission fragments from $^{235}$U($n_{th}$,$f$) following $��$ ray spectroscopy

Author: Dey, Aniruddha, Biswas, D. C., Chakraborty, A., Mukhopadhyay, S., Mondal, A. K., Danu, L. S., Mukherjee, B., Garg, S., Maheshwari, B., Jain, A. K., Blanc, A., de France, G., Jentschel, M., K��ster, U., Leoni, S., Mutti, P., Simpson, G., Soldner, T., Ur, C. A., and Urban, W.
Subjects: Nuclear Theory (nucl-th), FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: A detailed investigation on the relative isotopic distributions has been carried out for the first time in case of even-even correlated fission fragments for the $^{235}$U($n_{th}$,$f$) fission reaction. High-statistics data were obtained in a prompt $��$ ray spectroscopy measurement during the EXILL campaign at ILL, Grenoble, France. The extensive off-line analysis of the coincidence data have been carried out using four different coincidence methods. Combining the results from 2-dimensional $��-��$ and 3-dimensional $��-��-��$ coincidence analysis, a comprehensive picture of the relative isotopic yield distributions of the even-even neutron-rich fission fragments has emerged. The experimentally observed results have been substantiated by the theoretical calculations based on a novel approach of isospin conservation, and a reasonable agreement has been obtained. The calculations following the semi-empirical GEF model have also been carried out. The results from the GEF model calculations are found to be in fair agreement with the experimental results., Accepted in PRC; nucl-ex; nucl-th
Published: 2021
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2. Low-spin particle-core and hole-core excitations in $^{41,47,49}$Ca isotopes studied by cold-neutron-capture reactions

Author: Bottoni, S., Cieplicka-Oryńczak, N., Leoni, S., Fornal, B., Colò, G., Bortignon, P. F., Bocchi, G., Bazzacco, D., Benzoni, G., Blanc, A., Bracco, A., Ceruti, S., Crespi, F. C. L., de France, G., Gamba, E. R., Iskra, Ł. W., Jentschel, M., Köster, U., Michelagnoli, C., Million, B., Mengoni, D., Mutti, P., Niu, Y., Porzio, C., Simpson, G., Soldner, T., Szpak, B., Türler, A., Ur, C. A., Urban, W., Institut Laue-Langevin (ILL), ILL, 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), and 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)
Subjects: Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Nuclear Experiment (nucl-ex), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Structure, Nuclear Experiment
Abstract: We present recent results on the structure of the one-valence-particle $^{41}$Ca and $^{49}$Ca, and one-valence-hole $^{47}$Ca, nuclei. The isotopes of interest were populated via the cold-neutron capture reactions $^{40}$Ca(n,$\gamma$), $^{48}$Ca(n,$\gamma$) and $^{46}$Ca(n,$\gamma$), respectively. The experiments were performed at the Institut Laue-Langevin, within the EXILL campaign, which employed a large array of HPGe detectors. The $\gamma$ decay and level schemes of these nuclei were investigated by $\gamma$-ray coincidence relationships, leading to the identification of 41, 10, and 6 new transitions in $^{41}$Ca, $^{47}$Ca, and $^{49}$Ca, respectively. Branching ratios and intensities were extracted for the $\gamma$ decay from each state, and $\gamma$-ray angular correlations were performed to establish a number of transition multipolarities and mixing ratios, thus helping in the spin assignment of the states. The experimental findings are discussed along with microscopic, self-consistent beyond-mean-field calculations performed with the Hybrid Configuration Mixing model, based on a Skyrme SkX Hamiltonian. The latter suggests that a fraction of the low-spin states of the $^{41}$Ca, $^{49}$Ca, and $^{47}$Ca nuclei is characterized by the coexistence of either 2p-1h and 1p-2h excitations, or couplings between single-particle/hole degrees of freedom and collective vibrations (phonons) of the doubly-magic "core".
Published: 2021
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3. Low-spin particle-core and hole-core excitations in Ca 41 , 47 , 49 isotopes studied by cold-neutron-capture reactions

Author: Bottoni, S., Cieplicka-Ory��czak, N., Leoni, S., Fornal, B., Col��, G., Bortignon, P. F., Bocchi, G., Bazzacco, D., Benzoni, G., Blanc, A., Bracco, A., Ceruti, S., Crespi, F. C. L., de France, G., Gamba, E. R., Iskra, ��. W., Jentschel, M., K��ster, U., Michelagnoli, C., Million, B., Mengoni, D., Mutti, P., Niu, Y., Porzio, C., Simpson, G., Soldner, T., Szpak, B., T��rler, A., Ur, C. A., and Urban, W.
Subjects: 540 Chemistry, 570 Life sciences, biology
Published: 2021
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4. Low-spin particle-core and hole-core excitations in Ca 41,47,49 isotopes studied by cold-neutron-capture reactions

Author: Bottoni, S., Cieplicka-Orynczak, N., Leoni, S., Fornal, B., Colo, G., Bortignon, P. F., Bocchi, G., Bazzacco, D., Benzoni, G., Blanc, A., Bracco, A., Ceruti, S., Crespi, F. C. L., De France, G., Gamba, E. R., Iskra, L. W., Jentschel, M., Koster, U., Michelagnoli, C., Million, B., Mengoni, D., Mutti, P., Niu, Y., Porzio, C., Simpson, G., Soldner, T., Szpak, B., Turler, A., C. A., Ur, and Urban, W.
Published: 2021

5. High-precision spectroscopy of $^{65}$Ni via neutron capture

Author: Porzio, C., Michelagnoli, C., Cieplicka-Orynczak, N., Sferrazza, M., Leoni, S., Fornal, B., Tsunoda, Y., Otsuka, T., Bottoni, S., Costache, C., Crespi, F.C.L., Iskra, Ł.W., Jentschel, M., Kandzia, F., Kim, Y.H., Köster, U., Marginean, N., Mihai, C., Mutti, P., Turturica, A., Institut Laue-Langevin (ILL), and ILL
Subjects: [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract: International audience; Detailed studies of the low-spin structures of neutron-rich Ni isotopes may help shedding light on the shape coexistence phenomenon. Of particular interest is the 65Ni nucleus, since it lies between 64Ni and 66Ni, where shape coexistence has been reported earlier. A spectroscopic investigation of 65Ni has been performed at Institut Laue-Langevin via the reaction64Ni(n,γ) 65Ni, using the FIPPS HPGe array. Several new gamma transitions have been observed and angular correlation analyses have been performed. A comparison with Monte Carlo shell-model calculations pointed to a dominance of spherical states up to 1.5 MeV excitation energy, together with the appearance of two states of oblate character.
Published: 2020
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6. Shape Coexistence at Zero Spin in Ni-64 Driven by the Monopole Tensor Interaction

Author: Marginean, N, Little, D, Tsunoda, Y, Leoni, S, Janssens, RVF, Fornal, B, Otsuka, T, Michelagnoli, C, Stan, L, Crespi, FCL, Costache, C, Lica, R, Sferrazza, M, Turturica, A, Ayangeakaa, AD, Auranen, K, Barani, M, Bender, PC, Bottoni, S, Boromiza, M, Bracco, A, Calinescu, S, Campbell, CM, Carpenter, MP, Chowdhury, P, Ciemala, M, Cieplicka-Orynczak, N, Cline, D, Clisu, C, Crawford, HL, Dinescu, IE, Dudouet, J, Filipescu, D, Florea, N, Forney, AM, Fracassetti, S, Gade, A, Gheorghe, I, Hayes, AB, Harca, I, Henderson, J, Ionescu, A, Iskra, LW, Jentschel, M, Kandzia, F, Kim, YH, Kondev, FG, Korschinek, G, Koster, U, Krishichayan, Krzysiek, M, Lauritsen, T, Li, J, Marginean, R, Maugeri, EA, Mihai, C, Mihai, RE, Mitu, A, Mutti, P, Negret, A, Nita, CR, Olacel, A, Oprea, A, Pascu, S, Petrone, C, Porzio, C, Rhodes, D, Seweryniak, D, Schumann, D, Sotty, C, Stolze, SM, Suvaila, R, Toma, S, Ujeniuc, S, Walters, WB, Wu, CY, Wu, J, Zhu, S, and Ziliani, S
Subjects: Science & Technology, STATES, Physics, Physical Sciences, Physics, Multidisciplinary, TRANSITION
Abstract: The low-spin structure of the semimagic ^{64}Ni nucleus has been considerably expanded: combining four experiments, several 0^{+} and 2^{+} excited states were identified below 4.5 MeV, and their properties established. The Monte Carlo shell model accounts for the results and unveils an unexpectedly complex landscape of coexisting shapes: a prolate 0^{+} excitation is located at a surprisingly high energy (3463 keV), with a collective 2^{+} state 286 keV above it, the first such observation in Ni isotopes. The evolution in excitation energy of the prolate minimum across the neutron N=40 subshell gap highlights the impact of the monopole interaction and its variation in strength with N. ispartof: PHYSICAL REVIEW LETTERS vol:125 issue:10 ispartof: location:United States status: published
Published: 2020

7. Shape Coexistence at Zero Spin in 64Ni Driven by the Monopole Tensor Interaction

Author: Mărginean, N., Little, D., Tsunoda, Y., Leoni, S., Janssens, R.V.F., Fornal, B., Otsuka, T., Michelagnoli, C., Stan, L., Crespi, F.C.L., Costache, C., Lica, R., Sferrazza, M., Turturica, A., Ayangeakaa, A.D., Auranen, K., Barani, M., Bender, P.C., Bottoni, S., Boromiza, M., Bracco, A., Călinescu, S., Campbell, C.M., Carpenter, M.P., Chowdhury, P., Ciemała, M., `nczak, N. Cieplicka-Ory, Cline, D., Clisu, C., Crawford, H.L., Dinescu, I.E., Dudouet, J., Filipescu, D., Florea, N., Forney, A.M., Fracassetti, S., Gade, A., Gheorghe, I., Hayes, A.B., Harca, I., Henderson, J., Ionescu, A., Iskra, Ł.W., Jentschel, M., Kandzia, F., Kim, Y.H., Kondev, F.G., Korschinek, G., Köster, U., Krishichayan, M., Krzysiek, M., Lauritsen, T., Li, J., Mărginean, R., Maugeri, E.a., Mihai, C., Mihai, R.E., Mitu, A., Mutti, P., Negret, A., Niţă, C.R., Olăcel, A., Oprea, A., Pascu, S., Petrone, C., Porzio, C., Rhodes, D., Seweryniak, D., Schumann, D., Sotty, C., Stolze, S.M., Şuvăilă, R., Toma, S., Ujeniuc, S., Walters, W.B., Wu, C.Y., Wu, J., Zhu, S., Ziliani, S., Institut Laue-Langevin (ILL), ILL, Institut de Physique Nucléaire de Lyon (IPNL), 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)
Subjects: Nuclear Theory (nucl-th), [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Nuclear Theory, FOS: Physical sciences, Nuclear Experiment (nucl-ex), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Physique atomique et nucléaire, Nuclear Physics
Abstract: International audience; The low-spin structure of the semimagic Ni64 nucleus has been considerably expanded: combining four experiments, several 0+ and 2+ excited states were identified below 4.5 MeV, and their properties established. The Monte Carlo shell model accounts for the results and unveils an unexpectedly complex landscape of coexisting shapes: a prolate 0+ excitation is located at a surprisingly high energy (3463 keV), with a collective 2+ state 286 keV above it, the first such observation in Ni isotopes. The evolution in excitation energy of the prolate minimum across the neutron N=40 subshell gap highlights the impact of the monopole interaction and its variation in strength with N.
Published: 2020
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8. Low-Z boundary of the N = 88-90 shape phase transition: 148Ce near the critical point

Author: Koseoglou, P., Werner, V., Pietralla, N., Ilieva, S., Nikšić, T., Vretenar, D., Alexa, P., Thűrauf, M., Bernards, C., Blanc, A., Bruce, A. M., Cakirli, R. B., Cooper, N., Fraile, L. M., de France, G., Jentschel, M., Jolie, J., Kőster, U., Korten, W., Krőll, T., Lalkovski, S., Mach, H., Mărginean, N., Mutti, P., Patel, Z., Paziy, V., Podolyak, Zs., Regan, Patrick, Régis, J.-M., Roberts, O. J., Saed-Samii, N., Simpson, G. S., Soldner, T., Ur, C. A., Urban, W., Wilmsen, D., and Wilson, E.
Abstract: Excited states of the neutron-rich nucleus 148Ce have been populated by neutron-induced fission of 235U and 241Pu samples. Their electromagnetic decays were studied by means of γ-ray coincidence spectroscopy with fast-timing capabilities. Lifetimes of the 2+1 and 4+1 states of 148Ce were obtained and their E2 decay rates deduced. The B4=2 = B(E2; 4+1 → 2+1)=B(E2; 2+1 → 0+1) ratio indicates that 148Ce is a transitional nucleus while the N = 88/90 shape phase transition evolves into a gradual change of nuclear deformation for proton numbers Z < 60.
Published: 2020

9. Development of a liquid scintillator based active fission target for FIPPS

Author: Kandzia, F., Belier, G., Michelagnoli, C., Aupiais, J., Barani, M., Dudouet, J., Düllmann, Christoph Emanuel, Iskra, Ł. W., Jentschel, M., Kim, Y. H., Köster, U., Turturica, A., Institut Laue-Langevin (ILL), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Physique Nucléaire de Lyon (IPNL), 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)-Centre National de la Recherche Scientifique (CNRS), ILL, 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)
Subjects: ddc:530, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det]
Abstract: The European physical journal / A 56(8), 207 (2020). doi:10.1140/epja/s10050-020-00201-0, Published by Springer, Heidelberg
Published: 2020
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10. Lifetime measurements in the odd-A nucleus $^{177}$Hf

Author: Knafla, L., Alexa, P., Köster, U., Thiamova, G., Régis, J.M., Jolie, J., Blanc, A., Bruce, A.M., Esmaylzadeh, A., Fraile, L.M., De France, G., Häfner, G., Ilieva, S., Jentschel, M., Karayonchev, V., Korten, W., Kröll, T., Lalkovski, S., Leoni, S., Mach, H., Mărginean, N., Mutti, P., Pascovici, G., Paziy, V., Podolyák, Zs., Regan, P.H., Roberts, O.J., Saed-Samii, N., Simpson, G.S., Smith, J.F., Soldner, T., Townsley, C., Ur, C.A., Urban, W., Vancraeyenest, A., Warr, N., Institut Laue-Langevin (ILL), ILL, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), 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), 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), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay
Subjects: [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Structure
Abstract: International audience; Lifetimes of low- and high-spin states in the odd-A nucleus Hf177 were measured during the EXILL&FATIMA campaign using a spectrometer equipped with eight HPGe-Clover detectors and 16 fast-timing LaBr3(Ce) detectors. For the determination of lifetimes in the pico- to nanosecond regime, the well-established generalized centroid difference method was used. Lifetimes of the 9/2−, 9/2+, 11/2−, 11/2+ states were remeasured, the lifetimes of the 13/2−, 17/2−, 13/2+, 15/2+, and 17/2+ states were determined for the first time and an upper limit for the 19/2+ state has been established. From these lifetimes absolute reduced transition probabilities were extracted and compared to particle-rotor-model calculations and quasiparticle-phonon-model calculations showing the importance of including multipole-multipole interactions in the description of odd-A nuclei in the rare earth region.
Published: 2020
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11. Conceptual Design Report Jülich High Brilliance Neutron Source (HBS)

Author: Baggemann, J., Böhm, S., Doege, P., Fenske, J., Feygenson, M., Glavic, A., Holderer, O., Jaksch, S., Jentschel, M., Kleefisch, S., Kleines, H., Li, J., Lieutenant, K., Mastinu, P., Mauerhofer, E., Meusel, O., Pasini, S., Podlech, H., Rimmler, M., Rücker, U., Schrader, T., Schweika, Werner, Strobl, M., Vezhlev, E., Voigt, J., Zakalek, P., Zimmer, O., Brückel, Thomas, and Gutberlet, Thomas
Subjects: ddc:796
Abstract: Jülich : Forschungszentrum Jülich GmbH, Zentralbibliothek, Schriften des Forschungszentrums Jülich. Reihe Allgemeines 8, 197 Seiten : Illustrationen, Diagramme, Karten (2020)., Published by Forschungszentrum Jülich GmbH, Zentralbibliothek, Jülich
Published: 2020
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12. $\gamma$ spectroscopy of the $^{96}\mathrm{Y}$ isotope: Searching for the onset of shape coexistence before $N=60$

Author: Iskra, Ł. W., Leoni, S., Fornal, B., Michelagnoli, C., Kandzia, F., Mărginean, N., Barani, M., Bottoni, S., Cieplicka-Oryńczak, N., Colombi, G., Costache, C., Crespi, F.C.L., Dudouet, J., Jentschel, M., Kim, Y.H., Köster, U., Lica, R., Mărginean, R., Mihai, C., Mihai, R.E., Nita, C.R., Pascu, S., Porzio, C., Reygadas, D., Ruiz-Martinez, E., Turturica, A., Institut Laue-Langevin (ILL), ILL, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Nuclear Structure
Abstract: International audience; Medium and high spin states of the Y96 nucleus, located in the shape-coexistence region near Z=40 and N=60, were populated in thermal-neutron-induced fission of U233 and U235 targets, diluted in a scintillator. γ rays were measured with the FIssion Product Prompt γ-ray Spectrometer (FIPPS) high-purity germanium (HPGe) detector array, using double and triple γ-ray coincidence techniques and taking advantage of the efficient fission tag provided by the scintillating target material. A complex level scheme, extending up to 5.2 MeV and including excitations above the 8+β-decaying isomer, was investigated, and firm spin and parity assignments were given to a number of states, on the basis of angular correlation analysis and considerations on the γ-decay patterns. While the structures built on the 0− ground state and the 8+ isomer show irregular patterns typical for spherical shapes, the (6+) isomeric state at 1655 keV [with half-life of 181(9) ns], and the rotational band built on it [with spin-parity values between (6+) and (9+)], can be explained by Hartree-Fock-Bogoliubov calculations, if an oblate deformation is assumed. This is the first observation of a deformed structure in an N=57 isotone, lying three neutrons away from the N=60 line. An important finding is also the 115-keV transition which connects the (6+) 181(9)-ns isomer to the β-decaying 8+ spherical isomer, allowing us to firmly place the latter at 1541 keV excitation energy. This may be relevant for calculations of electron and antineutrino spectra from fission of actinides, for which Y96 is a prominent product.
Published: 2020
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13. Low- Z boundary of the N=88 –90 shape phase transition: Ce148 near the critical point

Author: Koseoglou, P., Werner, V., Pietralla, N., Ilieva, S., Nikšić, T., Vretenar, D., Alexa, P., Thürauf, M., Bernards, C., Blanc, A., Bruce, A. M., Cakirli, R. B., Cooper, N., Fraile, L. M., de France, G., Jentschel, M., Jolie, J., Köster, U., Korten, W., Kröll, T., Lalkovski, S., Mach, H., Mărginean, N., Mutti, P., Patel, Z., Paziy, V., Podolyák, Zs., Regan, P. H., Régis, J.-M., Roberts, O. J., Saed-Samii, N., Simpson, G. S., Soldner, T., Ur, C. A., Urban, W., Wilmsen, D., and Wilson, E.
Subjects: PRIRODNE ZNANOSTI. Fizika, atomic nuclei, collective excitations, shape phase transition, energy density functional, NATURAL SCIENCES. Physics
Abstract: Excited states of the neutron-rich nucleus 148Ce have been populated by neutron-induced fission of a 235U target. Its electromagnetic decays were studied by means of γ-ray coincidence spectroscopy with fast- timing capabilities. Lifetimes of the 2+1 and 4+1 states of 148Ce were obtained and their E2 decay rates deduced. The B4/2=B(E2 ; 4+1→2+1)/B(E2 ; 2+1→0+1) ratio indicates that 148Ce is a transitional nucleus while the N=88/90 shape phase transition evolves into a gradual change of nuclear deformation for proton numbers Z
Published: 2020
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14. Low-$Z$ boundary of the $N=88-90$ shape phase transition: $^{148}\mathrm{Ce}$ near the critical point

Author: Koseoglou, P., Werner, V., Pietralla, N., Ilieva, S., Nikšić, T., Vretenar, D., Alexa, P., Thürauf, M., Bernards, C., Blanc, A., Bruce, A.M., Cakirli, R.B., Cooper, N., Fraile, L.M., De France, G., Jentschel, M., Jolie, J., Köster, U., Korten, W., Kröll, T., Lalkovski, S., Mach, H., Mărginean, N., Mutti, P., Patel, Z., Paziy, V., Podolyák, Zs., Regan, P.H., Régis, J.M., Roberts, O.J., Saed-Samii, N., Simpson, G.S., Soldner, T., Ur, C.A., Urban, W., Wilmsen, D., Wilson, E., Institut Laue-Langevin (ILL), ILL, 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), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), 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 National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)
Subjects: Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Nuclear Structure
Abstract: International audience; Excited states of the neutron-rich nucleus Ce148 have been populated by neutron-induced fission of a U235 target. Its electromagnetic decays were studied by means of γ-ray coincidence spectroscopy with fast-timing capabilities. Lifetimes of the 21+ and 41+ states of Ce148 were obtained and their E2 decay rates deduced. The B4/2=B(E2;41+→21+)/B(E2;21+→01+) ratio indicates that Ce148 is a transitional nucleus while the N=88/90 shape phase transition evolves into a gradual change of nuclear deformation for proton numbers Z
Published: 2020
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15. Lifetime measurements in the odd−A nucleus $^{177}$Hf

Author: Knafla, L., Alexa, P., Köster, U., Thiamova, G., Régis, J.-M., Jolie, J., Blanc, A., Bruce, A., Esmaylzadeh, A., Fraile, L., De France, G., Häfner, G., Ilieva, S., Jentschel, M., Karayonchev, V., Korten, W., Kröll, T., Lalkovski, S., Leoni, S., Mach, H., Mărginean, N., Mutti, P., Pascovici, G., Paziy, V., Podolyák, Zs., Regan, P., Roberts, O., Saed-Samii, N., Simpson, G., Smith, J., Soldner, T., Townsley, C., Ur, C., Urban, W., Vancraeyenest, A., Warr, N., Institut für Kernphysik der Universität zu Köln, Universität zu Köln = University of Cologne, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut Laue-Langevin (ILL), 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 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), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Universität zu Köln, ILL, 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: [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract: International audience; Lifetimes of low- and high-spin states in the odd-A nucleus 177Hf were measured during the EXILL&FATIMA campaign using a spectrometer equipped with eight HPGe-Clover detectors and 16 fast-timing LaBr3(Ce) detectors. For the determination of lifetimes in the pico- to nanosecond regime, the well-established generalized centroid difference method was used. Lifetimes of the 9/2−, 9/2+, 11/2−, 11/2+ states were remeasured, the lifetimes of the 13/2−, 17/2−, 13/2+, 15/2+, and 17/2+ states were determined for the first time and an upper limit for the 19/2+ state has been established. From these lifetimes absolute reduced transition probabilities were extracted and compared to particle-rotor-model calculations and quasiparticle-phonon-model calculations showing the importance of including multipole-multipole interactions in the description of odd-A nuclei in the rare earth region.
Published: 2020
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16. Shape Coexistence at Zero Spin in Ni64 Driven by the Monopole Tensor Interaction

Author: Mărginean, N., Little, D., Tsunoda, Y., Leoni, S., Janssens, R. V. F., Fornal, B., Otsuka, T., Michelagnoli, C., Stan, L., Crespi, F. C. L., Costache, C., Lica, R., Sferrazza, M., Turturica, A., Ayangeakaa, A. D., Auranen, K., Barani, M., Bender, P. C., Bottoni, S., Boromiza, M., Bracco, A., Călinescu, S., Campbell, C. M., Carpenter, M. P., Chowdhury, P., Ciemała, M., Cieplicka-Oryǹczak, N., Cline, D., Clisu, C., Crawford, H. L., Dinescu, I. E., Dudouet, J., Filipescu, D., Florea, N., Forney, A. M., Fracassetti, S., Gade, A., Gheorghe, I., Hayes, A. B., Harca, I., Henderson, J., Ionescu, A., Iskra, Ł. W., Jentschel, M., Kandzia, F., Kim, Y. H., Kondev, F. G., Korschinek, G., Köster, U., Krishichayan, Krzysiek, M., Lauritsen, T., Li, J., Mărginean, R., Maugeri, E. A., Mihai, C., Mihai, R. E., Mitu, A., Mutti, P., Negret, A., Niţă, C. R., Olăcel, A., Oprea, A., Pascu, S., Petrone, C., Porzio, C., Rhodes, D., Seweryniak, D., Schumann, D., Sotty, C., Stolze, S. M., Şuvăilă, R., Toma, S., Ujeniuc, S., Walters, W. B., Wu, C. Y., Wu, J., Zhu, S., and Ziliani, S.
Subjects: ddc
Published: 2019

17. Fluorinated nanodiamonds as unique neutron reflector

Author: Dubois, M., Nesvizhevsky, V., Jentschel, M., Koester, U., Batisse, N., Frezet, L., Bosak, A., Gines, L., Williams, O., Institut de Chimie de Clermont-Ferrand (ICCF), SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), and Bonnefoy, Stéphanie
Subjects: [CHIM] Chemical Sciences, [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2019

18. Decay properties of the level 3$^-_1$ in $^{96}$Mo

Author: Gregor, E.T., Arsenyev, N.N., Scheck, M., Shneidman, T.M., Thürauf, M., Bernards, C., Blanc, A., Chapman, R., Drouet, F., Dzhioev, A.A., De France, G., Jentschel, M., Jolie, J., Keatings, J.M., Kröll, Th, Köster, U., Leguillon, R., Mashtakov, K.R., Mutti, P., O'Donnell, D., Petrache, C.M., Simpson, G.S., Sinclair, J., Smith, J.F., Soldner, T., Spagnoletti, P., Sushkov, A.V., Urban, W., Vancraeyenest, A., Vanhoy, J.R., Werner, V., Zell, K.O., Zielińska, M., Institut Laue-Langevin (ILL), ILL, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), 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 de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), 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 Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: High Energy Physics::Experiment, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract: International audience; The first excited level of 96Mo was investigated in a high-statistics experiment using the 95Mo(n, γγ) cold neutron capture reaction. The measurements used the high cold neutron flux from the research reactor at Institut Laue-Langevin and employed the highly-efficient EXILL array to detect γ-ray coincidences. The recorded statistics allow identification of decay branches with only a small relative intensity including the E3 decay. With the knowledge of the newly measured branching ratio and the known transition probability, the lifetime of the level was determined and, subsequently, the strength of the other decay branches of the octupole phonon were calculated. The extracted electromagnetic decay strengths are compared to the systematics of the stable even–even molybdenum isotopes and values calculated in a Skyrme-force based quasiparticle random phase approximation and in a cluster approach. Additionally, the decay branch to the low-lying quadrupole isovector level was observed.
Published: 2019
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19. Low-lying octupole isovector excitation in $^{144}$Nd

Author: Thürauf, M., Stoyanov, Ch., Scheck, M., Jentschel, M., Bernards, C., Blanc, A., Cooper, N., de France, G., Gregor, E.T., Henrich, C., Hicks, S.F., Jolie, J., Kaleja, O., Köster, U., Kröll, T., Leguillon, R., Mutti, P., O'Donnell, D., Petrache, C.M., Simpson, G.S., Smith, J.F., Soldner, T., Tezgel, M., Urban, W., Vanhoy, J., Werner, M., Werner, V., Zell, K.O., Zerrouki, T., Institut Laue-Langevin (ILL), ILL, 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), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), 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)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-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)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Structure
Abstract: International audience; The nature of low-lying 3− levels in Nd144 was investigated in the Nd143(n,γγ) cold neutron-capture reaction. The combination of the high neutron flux from the research reactor at the Institut Laue-Langevin and the high γ-ray detection efficiency of the EXILL setup allowed the recording of γγ coincidences. From the coincidence data precise branching ratios were extracted. Furthermore, the octagonal symmetry of the setup allowed angular-distribution measurements to determine multipole-mixing ratios. Additionally, in a second measurement the ultra-high resolution spectrometer GAMS6 was employed to conduct lifetime measurements using the gamma-ray induced Doppler-shift technique (GRID). The confirmed strong M1 component in the 33−→31− decay strongly supports the assignment of the 33− level at 2779keV as low-lying isovector octupole excitation. Microscopic calculations within the quasiparticle phonon model confirm an isovector component in the wave function of the 33− level, firmly establishing this fundamental mode of nuclear excitation in near-spherical nuclei.
Published: 2019
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20. Co-existing excitation modes in neutron rich nucleus- $^{98}$Zr

Author: Mondal, A.K., Mukhopadhyay, S., Chakraborty, A., Biswas, D.C., Danu, L.S., Blanc, A., De France, G., Jentschel, M., Köster, U., Leoni, S., Mutti, P., Simpson, G., Soldner, T., Ur, C.A., Urban, W., Institut Laue-Langevin (ILL), 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 Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), ILL, 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 National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)
Subjects: [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Nuclear Theory, Nuclear Experiment
Abstract: International audience; Neutron-rich nuclei in A∼100 mass region exhibits a variety of nuclear structure phenomena such as the existence of different excited 0+ deformed states, shape coexisting states, high spin single-particle isomeric states, octupole vibrational states etc [1,2]. We are reporting here the different coexisting excitation modes in the medium spin structures of 98Zr nucleus with the incorporation of the new spectroscopic results obtained from an experiment using the thermal neutron induced fission of 235U.
Published: 2018

21. The STEREO Experiment

Author: Allemandou , N., Almazán , H., Del Amo Sanchez , P., Bernard , L., Bernard , C., Blanchet , A., Bonhomme , A., Bosson , G., Bourrion , O., Bouvier , J., Buck , C., Caillot , V., Chala , M., Champion , P., Charon , P., Collin , A., Contrepois , P., Coulloux , G., Deleglise , G., El Kanawati , W., Favier , J., Fuard , S., Gomes Monteiro , I., Gramlich , B., Haser , J., Helaine , V., Heusch , M., Jentschel , M., Kandzia , F., Konrad , G., Köster , U., Kox , S., Lahonde-Hamdoun , C., Lamblin , J., Letourneau , A., Lhuillier , D., Li , C., Lindner , M., Manzanillas , L., Materna , T., Méplan , O., Minotti , A., Monon , C., Montanet , F., Nunio , F., Peltier , F., Penichot , Y., Pequignot , M., Pessard , H., Piret , Y., Prono , G., Quéméner , G., Real , J.-S., Roca , C., Salagnac , T., Sergeyeva , V., Schoppmann , S., Scola , L., Scordilis , J.-P., Soldner , T., Stutz , A., Tourres , D., Vescovi , C., Zsoldos , S., Laboratoire d'Annecy de Physique des Particules ( LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules ), Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Physique Subatomique et de Cosmologie ( LPSC ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut polytechnique de Grenoble - Grenoble Institute of Technology ( Grenoble INP ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ), Service des Réacteurs et de Mathématiques Appliquées ( SERMA ), Département de Modélisation des Systèmes et Structures ( DM2S ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Institut Laue-Langevin ( ILL ), ILL, Ecole Nationale Supérieure d'Ingénieurs de Caen ( ENSICAEN ), Normandie Université ( NU ), and STEREO
Subjects: neutrino: detector, Physics::Instrumentation and Detectors, shielding, [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], antineutrino: nuclear reactor, High Energy Physics::Experiment, neutrino: sterile, [ PHYS.PHYS.PHYS-INS-DET ] Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], detector: design, background: suppression, performance, activity report, Physics::Geophysics
Abstract: The STEREO experiment is a very short baseline reactor antineutrino experiment aiming at testing the hypothesis of light sterile neutrinos as an explanation of the deficit of the observed neutrino interaction rate with respect to the predicted rate, known as the Reactor Antineutrino Anomaly. The detector center is located 10 m away from the compact, highly $^{235}$U enriched core of the research nuclear reactor of the Institut Laue Langevin in Grenoble, France. This paper describes the STEREO site, the detector components and associated shielding designed to suppress the external sources of background which were characterized on site. It reports the performances in terms of detector response and energy reconstruction.
Published: 2018

22. EXILL—a high-efficiency, high-resolution setup for $\gamma$-spectroscopy at an intense cold neutron beam facility

Author: Jentschel, M., Blanc, A., De France, G., Köster, U., Leoni, S., Mutti, P., Simpson, G., Soldner, T., Ur, C., Urban, W., Ahmed, S., Astier, A., Augey, L., Back, T., Ba̧czyk, P., Bajoga, A., Balabanski, D., Belgya, T., Benzoni, G., Bernards, C., Biswas, D.C., Bocchi, G., Bottoni, S., Britton, R., Bruyneel, B., Burnett, J., Cakirli, R.B., Carroll, R., Catford, W., Cederwall, B., Celikovic, I., Cieplicka-Oryńczak, N., Clement, E., Cooper, N., Crespi, F., Csatlos, M., Curien, D., Czerwiński, M., Danu, L.S., Davies, A., Didierjean, F., Drouet, F., Duchêne, G., Ducoin, C., Eberhardt, K., Erturk, S., Fraile, L.M., Gottardo, A., Grente, L., Grocutt, L., Guerrero, C., Guinet, D., Hartig, A.L., Henrich, C., Ignatov, A., Ilieva, S., Ivanova, D., John, B.V., John, R., Jolie, J., Kisyov, S., Krticka, M., Konstantinopoulos, T., Korgul, A., Krasznahorkay, A., Kröll, T., Kurpeta, J., Kuti, I., Lalkovski, S., Larijani, C., Leguillon, R., Lica, R., Litaize, O., Lozeva, R., Magron, C., Mancuso, C., Martinez, E.Ruiz, Massarczyk, R., Mazzocchi, C., Melon, B., Mengoni, D., Michelagnoli, C., Million, B., Mokry, C., Mukhopadhyay, S., Mulholland, K., Nannini, A., Napoli, D.R., Olaizola, B., Orlandi, R., Patel, Z., Paziy, V., Petrache, C., Pfeiffer, M., Pietralla, N., Podolyak, Z., Ramdhane, M., Redon, N., Regan, P., Regis, J.M., Regnier, D., Oliver, R.J., Rudigier, M., Runke, J., Rza̧ca-Urban, T., Saed-Samii, N., Salsac, M.D., Scheck, M., Schwengner, R., Sengele, L., Singh, P., Smith, J., Stezowski, O., Szpak, B., Thomas, T., Thürauf, M., Timar, J., Tom, A., Tomandl, I., Tornyi, T., Townsley, C., Tuerler, A., Valenta, S., Vancraeyenest, A., Vandone, V., Vanhoy, J., Vedia, V., Warr, N., Werner, V., Wilmsen, D., Wilson, E., Zerrouki, T., Zielinska, M., Institut Laue-Langevin (ILL), ILL, 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 Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), 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)-Centre National de la Recherche Scientifique (CNRS), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-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), Institut National Polytechnique de Grenoble (INPG), CEA Cadarache, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), Institut Laue-Langevin ( ILL ), 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 Subatomique et de Cosmologie ( LPSC ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut polytechnique de Grenoble - Grenoble Institute of Technology ( Grenoble INP ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ), Centre de Sciences Nucléaires et de Sciences de la Matière ( CSNSM ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Physique Nucléaire de Lyon ( IPNL ), 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 ) -Centre National de la Recherche Scientifique ( CNRS ), Département de Physique Nucléaire (ex SPhN) ( DPHN ), Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-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 ), Institut National Polytechnique de Grenoble ( INPG ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), 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 ), Werner, Volker -- 0000-0003-4001-0150, Regnier, David -- 0000-0002-0345-7271, Britton, Richard -- 0000-0001-8532-8504, Cederwall, Bo -- 0000-0003-1771-2656, Valenta, Stanislav -- 0000-0003-2479-1380, Schwengner, Ronald -- 0000-0002-7620-8882, Olaizola, Bruno -- 0000-0003-1604-0640, nannini, adriana -- 0000-0003-0659-7648, Lica, Razvan -- 0000-0001-7066-9787, Petrache, Costel -- 0000-0001-8419-1390, Scheck, Marcus -- 0000-0002-9624-3909, Fraile, Luis M -- 0000-0002-6281-3635, Napoli, Daniel R. -- 0000-0002-8154-6958, Soldner, Torsten -- 0000-0003-2468-5182, GOTTARDO, Andrea -- 0000-0002-0390-5767, Belgya, Tamas -- 0000-0003-4281-5470, Wilson, Emma -- 0000-0003-2695-9853, Clement, Emmanuel -- 0000-0003-1887-717X, de France, Gilles -- 0000-0002-7439-1759, Vedia, Victoria -- 0000-0001-6671-3888, Celikovic, Igor -- 0000-0002-5642-4393, Lozeva, Radomira -- 0000-0002-0024-7068, Lalkovski, Stefan -- 0000-0003-3069-9708, Bottoni, Simone -- 0000-0003-2249-4825, [Jentschel, M. -- Blanc, A. -- Koster, U. -- Mutti, P. -- Soldner, T. -- Urban, W. -- Michelagnoli, C.] Inst Laue Langevin, 71 Ave Martyrs, F-38042 Grenoble 9, France -- [de France, G. -- Celikovic, I. -- Clement, E. -- Michelagnoli, C.] GANIL, Bvd Becquerel,BP 55027, F-14076 Caen 05, France -- [Leoni, S. -- Benzoni, G. -- Bocchi, G. -- Bottoni, S. -- Crespi, F. -- Million, B. -- Vandone, V.] Univ Milan, Dipartimento Fis, Via Celoria 16, I-20133 Milan, Italy -- [Simpson, G.] Univ Grenoble Alpes, LPSC, F-38026 Grenoble, France -- [Ur, C.] Univ Padua, Dipartimento Fis, Via F Marzolo 8, I-35131 Padua, Italy -- [Ur, C. -- Balabanski, D.] ELI NP, IFIN HH30, Bucharest 077125, Romania -- [Urban, W. -- Czerwinski, M. -- Korgul, A. -- Kurpeta, J. -- Mazzocchi, C.] Univ Warsaw, Fac Phys, Ul Pasteura 5, PL-02093 Warsaw, Poland -- [Pfeiffer, M. -- Regis, J. M. -- Saed-Samii, N. -- Thomas, T. -- Warr, N.] Univ Cologne, IKP, Zulpicher Str 77, D-50937 Cologne, Germany -- [Astier, A. -- Konstantinopoulos, T. -- Lozeva, R. -- Petrache, C. -- Zerrouki, T.] Univ Paris Saclay, CNRS, IN2P3, CSNSM, F-91405 Orsay, France -- [Augey, L. -- Guinet, D. -- Redon, N. -- Stezowski, O.] Lyon Univ Claude Bernard, IPN, 43 Blvd 11 Nov 1918, F-69622 Villeurbanne, France -- [Back, T. -- Cederwall, B.] KTH, Phys Dept, Roslagstullsbacken 21, S-10044 Stockholm, Sweden -- [Bajoga, A. -- Britton, R. -- Carroll, R. -- Catford, W. -- Davies, A. -- Lalkovski, S. -- Patel, Z. -- Podolyak, Z. -- Regan, P. -- Rudigier, M. -- Tom, A.] Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England -- [Balabanski, D.] INRNE Sofia, 72 Tzarigradsko Shaussee, Sofia 1784, Bulgaria -- [Belgya, T.] Hungarian Acad Sci CER, Konkoly T St 29-33, H-1121 Budapest, Hungary -- [Bernards, C. -- Cooper, N. -- Werner, V.] Yale Univ, Dept Phys, POB 208120, New Haven, CT 06520 USA -- [Biswas, D. C. -- Danu, L. S. -- John, B. V. -- Mukhopadhyay, S.] Bhabha Atom Res Ctr, Nucl Phys Div, Mumbai 400085, Maharashtra, India -- [Bruyneel, B. -- Grente, L. -- Salsac, M. D. -- Zielinska, M.] CEA Saclay ORME Merisiers, DSM IRFU SPHN, Bat 703, F-91191 Gif Sur Yvette, France -- [Burnett, J.] AWE PLC, Reading RG7 4PR, Berks, England -- [Cakirli, R. B.] Istanbul Univ, Dept Phys, TR-34134 Istanbul, Turkey -- [Cieplicka-Oryn'czak, N. -- Szpak, B.] Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland -- [Csatlos, M. -- Krasznahorkay, A. -- Kuti, I. -- Timar, J. -- Tornyi, T.] Hungarian Acad Sci, Inst Nucl Res, H-4001 Debrecen, Hungary -- [Curien, D. -- Didierjean, F. -- Duche'ne, G. -- Lozeva, R. -- Sengele, L.] Univ Strasbourg, CNRS, IPHC, UMR 7178, F-67000 Strasbourg, France -- [Drouet, F. -- Vancraeyenest, A.] INPG PHELMA, 3 Parvis Louis Neel BP 257, F-38000 Grenoble 1, France -- [Eberhardt, K. -- Mokry, C. -- Runke, J.] Johannes Gutenberg Univ Mainz, Inst Kernchem, Fritz Strassmann Weg 2, D-55128 Mainz, Germany -- [Erturk, S.] Nigde Univ, Merkez Yerleske Bor Yolu Uzeri, TR-51240 Nigde, Turkey -- [Fraile, L. M. -- Olaizola, B. -- Paziy, V. -- Vedia, V.] Univ Complutense, Grp Fis Nucl, Fis Avda Complutense, Madrid 28040, Spain -- [Gottardo, A. -- Napoli, D. R. -- Wilson, E.] INFN, Lab Nazl Legnaro, Vialle Univ 2, I-35020 Legnaro, Italy -- [Grocutt, L. -- Mulholland, K. -- Scheck, M. -- Smith, J.] Univ West Scotland, High St, Paisley PA1 2BE, Renfrew, Scotland -- [Guerrero, C.] CERN, CH-1211 Geneva 23, Switzerland -- [Hartig, A. -L. -- Henrich, C. -- Ignatov, A. -- Ilieva, S. -- Kroell, T. -- Pietralla, N. -- Thuerauf, M. -- Werner, V.] Tech Univ Darmstadt, IKP, Schlossgartenstr 9, D-64289 Darmstadt, Germany -- [Ivanova, D. -- Kisyov, S.] Univ Sofia, Fac Phys, 5 James Bourchier Blvd, Sofia 1126, Bulgaria -- [John, R. -- Massarczyk, R. -- Schwengner, R.] Helmholtz Zentrum Dresden Rossendorf, POB 510119, D-01314 Dresden, Germany -- [Larijani, C.] Natl Phys Lab, Teddington Queens Rd, Teddington, Middx, England -- [Leguillon, R. -- Orlandi, R.] JAEA, Tokai Shirakata Shirane 2-4 Tokai, Naka, Ibaraki 3191195, Japan -- [Lica, R.] IFIN HH, Bucharest Str Atomistilor 407,POB MG 6, Bucharest 76900, Romania -- [Litaize, O. -- Regnier, D.] CEA Cadarache, F-13108 St Paul Les Durance, France -- [Magron, C.] Univ Bordeaux, CENBG Bordeaux, 1 Le Haut Vigneau, F-33170 Gradignan, France -- [Magron, C.] Univ Firenze, Dipartimento Fis & Astron, Via G Sansone 1, I-50019 Florence, Italy -- [Melon, B.] INFN, Sez Firenze, Via G Sansone 1, I-50019 Sesto Fiorentino, Italy -- [Ramdhane, M.] LPSC Grenoble, 53 Ave Martyrs, F-38026 Grenoble, France -- [Oliver, R. J.] Univ Brighton, Sch Environm & Technol, Lewes Rd, Brighton, E Sussex BN2 4GJ, England -- [Singh, P.] Tata Inst Fundamental Res, Homi Bhabha Rd, Mumbai 400005, Maharashtra, India -- [Tomandl, I.] ASCR, Nucl Phys Inst, Rez 25068, Czech Republic -- [Townsley, C.] Univ Sussex, Sch Sci & Technol, Brighton BN1 9QJ, E Sussex, England -- [Tuerler, A.] Univ Bern, Dept Chem & Biochem, Freiestr 3, CH-3012 Bern, Switzerland -- [Krticka, M. -- Valenta, S.] Prague Charles Univ, Fac Math & Phys, Ke Karlovu 5, Prague 12116, Czech Republic -- [Vanhoy, J.] US Naval Acad, Dept Phys, 572C Holloway Rd, Annapolis, MD 21402 USA, 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 National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), 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), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), 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 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: Instrumentation for neutron sources, Spectrometers, Physics::Instrumentation and Detectors, Gamma detectors (scintillators, CZT, HPG, HgI etc), [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Detectors and Experimental Techniques, [ PHYS.PHYS.PHYS-INS-DET ] Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det]
Abstract: WOS: 000414625700003, In the EXILL campaign a highly efficient array of high purity germanium (HPGe) detectors was operated at the cold neutron beam facility PF1B of the Institut Laue-Langevin (ILL) to carry out nuclear structure studies, via measurements of gamma-rays following neutron-induced capture and fission reactions. The setup consisted of a collimation system producing a pencil beam with a thermal capture equivalent flux of about 10(8) ns(-1)cm(2) at the target position and negligible neutron halo. The targetwas surrounded by an array of eight to ten anti-Compton shielded EXOGAMClover detectors, four to six anti-Compton shielded large coaxial GASP detectors and two standard Clover detectors. For a part of the campaign the array was combined with 16 LaBr3:(Ce) detectors from the FATIMA collaboration. The detectorswere arranged in an array of rhombicuboctahedron geometry, providing the possibility to carry out very precise angular correlation and directional-polarization correlation measurements. The triggerless acquisition system allowed a signal collection rate of up to 6 x 10(5) Hz. The data allowed to set multi-fold coincidences to obtain decay schemes and in combination with the FATIMA array of LaBr3:(Ce) detectors to analyze half-lives of excited levels in the pico-to microsecond range. Precise energy and efficiency calibrations of EXILL were performed using standard calibration sources of Ba-133, Co-60 and Eu-152 as well as data from the reactions Al-27(n, gamma)Al-28 and Cl-35(n,gamma)Cl-36 in the energy range from 30 keV up to 10MeV., U.S. DOE grant [DE-FG02-91ER40609]; NUPNET; German BMBF [O5P12PKNUF, 05P15RDFN1, 05P12RDNUP]; German DFG contract [KR 1796/2-1]; Polish National Science Centre [DEC-2013/09/B/ST2/03485], This work has been partly supported by the Polish National Science Centre under contract DEC-2013/09/B/ST2/03485, the U.S. DOE grant No. DE-FG02-91ER40609, the NUPNET and the German BMBF under contracts O5P12PKNUF, 05P15RDFN1 and 05P12RDNUP and the German DFG contract KR 1796/2-1.
Published: 2017
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23. Lifetime measurements in $^{156}$Gd

Author: Aprahamian, A., De Haan, R.C., Lesher, S.R., Casarella, C., Stratman, A., Börner, H.G., Lehmann, H., Jentschel, M., Bruce, A.M., Institut Laue-Langevin (ILL), and ILL
Subjects: [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Structure
Abstract: International audience; Background: The nature of low-lying oscillations or excitations around the equilibrium deformed nuclear shape remains an open question in a nuclear structure. The question revolves around the possible degrees of freedom in deformed nuclei. Rotational motion is an expected feature of deformed nuclei; the open challenge is whether the “granularity” of the nuclei allows single or multiple quanta of vibrational oscillations or excitations superimposed on the equilibrium deformed shape of the nucleus. Special emphasis is placed on the Kπ=0+,β vibration whose existence is open to debate some 40 years after Bohr-Mottelson-Rainwater's Nobel prize for connecting nucleon motion to the emergence of collectivity. Purpose: The Gd156 nucleus is an excellent test case for the search of the predicted oscillations since it has one of the most developed level schemes up to 2.35 MeV and it lies in the well-deformed rare-earth region of the chart of nuclides. This nucleus has previously been studied by (n,γ),(n,e−),(e,e′),(p,p′),(d,p), and (d,t) reactions with six known excited Kπ=0+ bands. We measured level lifetimes of Gd156 in order to determine the nature of the low-lying excited bands. Method: The lifetimes of the excited states in the Gd156 nucleus were measured following neutron capture using the grid technique at the Institut Laue-Langevin in Grenoble, France. Results: Twelve level lifetimes were measured from four excitation bands in the Gd156 nucleus including the lifetimes of three of the Kπ=0+ bands. Conclusions: There are two Kπ=0+ bands in this nucleus connected to the ground-state band. Transitions from the Kπ=02+ band at 1049.5 keV to the ground-state band are more collective than the ones from the Kπ=03+ band at 1168.2 keV. The moments of inertia of the various Kπ=0+, the Kπ=2+, and the Kπ=4+ bands show that all the bands except the Kπ=03+ band at 1168.2 keV have nearly identical moments of inertia with the ground-state band pointing to the fact that all of the bands discussed here with the exception of this indicating Kπ=03+ band seem to be collective excitations built on the ground state. This result is consistent with various theoretical predictions. B(E2) calculations for transitions from the Kπ=2+ band to the ground-state band supports the assignment of this band as the γ band. Also, the Kπ=04+ and the Kπ=41+ bands at 1715.2 and 1510.6 keV, respectively, are shown to be strongly connected to the Kπ=2+γ band presenting evidence for the observation of a second set of two-phonon γγ vibrational excitations albeit with greatly varying degrees of anharmonicity in comparison to the case of Er166.
Published: 2018
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24. Dispersive refraction of different light-to-heavy materials at MeV $��$-ray energies

Author: G��nther, M. M., Volotka, A. V., Jentschel, M., Fritzsche, S., St��hlker, Th., Thirolf, P. G., and Zepf, M.
Subjects: Atomic Physics (physics.atom-ph), FOS: Physical sciences
Abstract: The dispersive behavior of materials with atomic charge numbers varing from $Z = 4$ (beryllium, Be) to $Z = 82$ (lead, Pb) was investigated experimentally and theoretically at $��$-ray energies up to 2 MeV. The experiment was performed at the double-crystal gamma spectrometer GAMS6 of the ILL in Grenoble. The experimental results were compared with theoretical calculations which account for all major elastic processes involved. Overall, we found a good agreement between theory and experiment. We find that for the development of refractive optics at $��$-ray energies beyond those currently in use high-Z materials become increasingly attractive compared to the beryllium lens-stacks used at X-ray energies., submitted to Phys. Rev. A
Published: 2018
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25. Low-spin excitations in $^{97}$Zr

Author: Rząca-Urban, T., Urban, W., Czerwiński, M., Wiśniewski, J., Blanc, A., Faust, H., Jentschel, M., Mutti, P., Köster, U., Soldner, T., de France, G., Simpson, G.S., Ur, C.A., Institut Laue-Langevin (ILL), ILL, 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 Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), 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 National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Nuclear Structure
Abstract: International audience; The main goal of this work is the determination of spins and parities of excited states in Zr97, among others the 2264.3-keV level, which had previously been tentatively reported as the 11/2− excitation corresponding to the h11/2 neutron orbital. Low-spin excited states in Zr97 were populated via the cold-neutron capture reaction. The γ rays emitted following the reaction were measured using the highly efficient array of high-purity germanium detectors, EXILL, at the Institut-Laue-Langevin (ILL), Grenoble. The primary γ rays deexciting the capture state in Zr97 were identified for the first time. The new, precise neutron binding energy in Zr97 of 5569.15(4) keV differs significantly from the value reported in the literature. The previously reported level scheme has been amended by several new low-spin levels. The (n,γ) data were complemented by a measurement of the β− decay of Y97 at the Lohengrin fission-fragment separator of the ILL, and the observation of the β− decay of Y97 populated in neutron-induced fission of U235 and measured using the EXILL Ge array. The combined data allowed unique spin-parity assignments for many levels in Zr97. The 2264.3-keV level, with a new spin-parity assignment of 9/2+, may correspond to the νg9/2 extruder orbital.
Published: 2018
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26. Experimental study of the lifetime and phase transition in neutron-rich 98,100,102Zr

Author: Ansari, S, Régis, J-M, Jolie, J, Saed-Samii, N, Warr, N, Korten, W, Zielińska, M, Salsac, M-D, Blanc, A, Jentschel, M, Köster, U, Mutti, P, Soldner, T, Simpson, GS, Drouet, F, Vancraeyenest, A, de France, G, Clément, E, Stezowski, O, Ur, CA, Urban, W, Regan, PH, Podolyák, Zs, Larijani, C, Townsley, C, Carroll, R, Wilson, E, Mach, H, Fraile, LM, Paziy, V, Olaizola, B, Vedia, V, Bruce, AM, Roberts, OJ, Smith, JF, Scheck, M, Kröll, T, Hartig, A-L, Ignatov, A, Ilieva, S, Lalkovski, S, Mărginean, N, Otsuka, Taka, Shimizu, N, Togashi, T, and Tsunoda, Y
Subjects: Nuclear Experiment
Abstract: Rapid shape changes are observed for neutron-rich nuclei with A around 100. In particular, a sudden onset of ground-state deformation is observed in the Zr and Sr isotopic chains at N = 60: Low-lying states in N≤58 nuclei are nearly spherical, while those with N≥60 have a rotational character. Nuclear lifetimes as short as a few picoseconds can be measured using fast-timing techniques with LaBr3(Ce) scintillators, yielding a key ingredient in the systematic study of the shape evolution in this region. We used neutron-induced fission of 241Pu and 235U to study lifetimes of excited states in fission fragments in the A∼100 region with the EXILL-FATIMA array located at the PF1B cold neutron beam line at the Institut Laue-Langevin. In particular, we applied the generalized centroid difference method to deduce lifetimes of low-lying states for the nuclei 98Zr (N = 58), 100Zr, and 102Zr (N≥60). The results are discussed in the context of the presumed phase transition in the Zr chain by comparing the experimental transition strengths with the theoretical calculations using the interacting boson model and the Monte Carlo shell model. ispartof: Physical Review C vol:96 issue:5 status: published
Published: 2017

27. EXILL—a high-efficiency, high-resolution setup for γ-spectroscopy at an intense cold neutron beam facility

Author: Jentschel, M., Blanc, A., de France, G., Köster, U., Leoni, S., Mutti, P., Simpson, G., Soldner, T., Ur, C., Urban, W., Ahmed, S., Astier, A., Augey, L., Back, T., Ba̧czyk, P., Bajoga, A., Balabanski, D., Belgya, T., Benzoni, G., Bernards, C., Biswas, D.C., Bocchi, G., Bottoni, S., Britton, R., Bruyneel, B., Burnett, J., Cakirli, R.B., Carroll, R., Catford, W., Cederwall, B., Celikovic, I., Cieplicka-Oryńczak, N., Clement, E., Cooper, N., Crespi, F., Csatlos, M., Curien, D., Czerwiński, M., Danu, L.S., Davies, A., Didierjean, F., Drouet, F., Duchêne, G., Ducoin, C., Eberhardt, K., Erturk, S., Fraile, L.M., Gottardo, A., Grente, L., Grocutt, L., Guerrero, C., Guinet, D., Hartig, A.-L., Henrich, C., Ignatov, A., Ilieva, S., Ivanova, D., John, B.V., John, R., Jolie, J., Kisyov, S., Krticka, M., Konstantinopoulos, T., Korgul, A., Krasznahorkay, A., Kröll, T., Kurpeta, J., Kuti, I., Lalkovski, S., Larijani, C., Leguillon, R., Lica, R., Litaize, O., Lozeva, R., Magron, C., Mancuso, C., Martinez, E. Ruiz, Massarczyk, R., Mazzocchi, C., Melon, B., Mengoni, D., Michelagnoli, C., Million, B., Mokry, C., Mukhopadhyay, S., Mulholland, K., Nannini, A., Napoli, D.R., Olaizola, B., Orlandi, R., Patel, Z., Paziy, V., Petrache, C., Pfeiffer, M., Pietralla, N., Podolyak, Z., Ramdhane, M., Redon, N., Regan, P., Regis, J.M., Regnier, D., Oliver, R. J., Rudigier, M., Runke, J., Rza̧ca-Urban, T., Saed-Samii, N., Salsac, M.D., Scheck, M., Schwengner, R., Sengele, L., Singh, P., Smith, J., Stezowski, O., Szpak, B., Thomas, T., Thürauf, M., Timar, J., Tom, A., Tomandl, I., Tornyi, T., Townsley, C., Türler, Andreas, Valenta, S., Vancraeyenest, A., Vandone, V., Vanhoy, J., Vedia, V., Warr, N., Werner, V., Wilmsen, D., Wilson, E., Zerrouki, T., and Zielinska, M.
Subjects: Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, 540 Chemistry, 570 Life sciences, biology
Abstract: In the EXILL campaign a highly efficient array of high purity germanium (HPGe) detectors was operated at the cold neutron beam facility PF1B of the Institut Laue-Langevin (ILL) to carry out nuclear structure studies, via measurements of γ-rays following neutron-induced capture and fission reactions. The setup consisted of a collimation system producing a pencil beam with a thermal capture equivalent flux of about 108 n s−1cm−2 at the target position and negligible neutron halo. The target was surrounded by an array of eight to ten anti-Compton shielded EXOGAM Clover detectors, four to six anti-Compton shielded large coaxial GASP detectors and two standard Clover detectors. For a part of the campaign the array was combined with 16 LaBr3:(Ce) detectors from the FATIMA collaboration. The detectors were arranged in an array of rhombicuboctahedron geometry, providing the possibility to carry out very precise angular correlation and directional-polarization correlation measurements. The triggerless acquisition system allowed a signal collection rate of up to 6 × 105 Hz. The data allowed to set multi-fold coincidences to obtain decay schemes and in combination with the FATIMA array of LaBr3:(Ce) detectors to analyze half-lives of excited levels in the pico- to microsecond range. Precise energy and efficiency calibrations of EXILL were performed using standard calibration sources of 133Ba, 60Co and 152Eu as well as data from the reactions 27Al(n,γ)28Al and 35Cl(n,γ)36Cl in the energy range from 30 keV up to 10 MeV.
Published: 2017
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28. Abrupt shape transition at neutron number N=60 : B(E2) values in Sr94,96,98 from fast γ−γ timing

Author: Régis, J.-M., Jolie, J., Saed-Samii, N., Warr, N., Pfeiffer, M., Blanc, A., Jentschel, M., Köster, U., Mutti, P., Soldner, T., Simpson, G. S., Drouet, F., Vancraeyenest, A., de France, G., Clément, E., Stezowski, O., Ur, C. A., Urban, W., Regan, Patrick, Podolyak, Zsolt, Larijani, Cyrus Kouroush, Townsley, C., Carroll, R., Wilson, E., Fraile, L. M., Mach, H., Paziy, V., Olaizola, B., Vedia, V., Bruce, A. M., Roberts, O. J., Smith, J. F., Scheck, M., Kröll, T., Hartig, A.-L., Ignatov, A., Ilieva, S., Lalkovski, S., Korten, W., Mărginean, N., Otsuka, T., Shimizu, N., Togashi, T., and Tsunoda, Y.
Subjects: Nuclear Theory, Nuclear Experiment
Abstract: Lifetimes of low-lying yrast states in neutron-rich 94,96,98Sr have been measured by Germanium-gated γ−γ fast timing with LaBr3(Ce) detectors using the EXILL&FATIMA spectrometer at the Institut Laue-Langevin. Sr fission products were generated using cold-neutron-induced fission of 235U and stopped almost instantaneously within the thick target. The experimental B(E2) values are compared with results of Monte Carlo shell-model calculations made without truncation on the occupation numbers of the orbits spanned by eight proton and eight neutron orbits and show good agreement. Similarly to the Zr isotopes, the abrupt shape transition in the Sr isotopes near neutron number N=60 is identified as being caused by many-proton excitations to its g9/2 orbit.
Published: 2017

29. Shape coexistence at zero spin in 64Ni driven by the monopole tensor interaction

Author: Mărginean, N., Little, D., Tsunoda, Y., Leoni, S., Janssens, R.V.F., Fornal, B., Michelagnoli, C., Stan, L., Crespi, F.C.L., Lică, R., Sferrazza, M., Turturica, A., Ayangeakaa, A.D., Auranen, K., Barani, M., Bender, P.C., Bottoni, S., Boromiza, M., Bracco, A., Călinescu, S., Campbell, C.M., Carpenter, M.P., Chowdhury, P., Ciemała, M., Cieplicka-Oryńczak, N., Cline, D., Clisu, C., Crawford, H.L., Dinescu, I.E., Dudouet, J., Florea, N., Forney, A.M., Fracassetti, S., Gade, A., Gheorghe, I., Hayes, A.B., Harca, I., Henderson, J., Ionescu, A., Iskra, Ł.W., Jentschel, M., Kandzia, F., Kim, Y.H., Kondev, F.G., Korschinek, G., Köster, U., Krzysiek, M., Lauritsen, T., Li, J., Mărginean, R., Maugeri, E.A., Mihai, R.E., Mitu, A., Mutti, P., Negret, A., Niţă, C.R., Olăcel, A., Oprea, A., Pascu, S., Petrone, C., Porzio, C., Rhodes, D., Schumann, D., Sotty, C., Stolze, S.M., Şuvăilă, R., Toma, S., Ujeniuc, S., Walters, W.B., Wu, C.Y., Wu, J., Zhu, S., and Ziliani, S.
Subjects: Nuclear Theory
Abstract: The low-spin structure of the semimagic 64Ni nucleus has been considerably expanded: combining four experiments, several 0+ and 2+ excited states were identified below 4.5 MeV, and their properties established. The Monte Carlo shell model accounts for the results and unveils an unexpectedly complex landscape of coexisting shapes: a prolate 0+ excitation is located at a surprisingly high energy (3463 keV), with a collective 2+ state 286 keV above it, the first such observation in Ni isotopes. The evolution in excitation energy of the prolate minimum across the neutron N=40 subshell gap highlights the impact of the monopole interaction and its variation in strength with N.
Published: 2020

30. The $\gamma-\gamma$ fast-timing technique and the EXILL&FATIMA campaign

Author: Régis, J.-M., Simpson, G.S., Mach, H., Blanc, A., Jentschel, M., Köster, U., Mutti, P., Soldner, T., De France, G., Ur, C.A., Urban, W., Jolie, J., Saed-Samii, N., Warr, N., Fraile, L.M., Paziy, V., Regan, P.H., Podolyák, Zs., Lalkovski, S., Bruce, A.M., Kröll, T., Korten, W., Marginean, N., Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut Laue-Langevin (ILL), 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), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), ILL, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), 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: [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract: International audience; At the Institut Laue-Langevin in Grenoble, germanium-gated γ-γ fast-timing lifetime measurements of nuclear excited states in neutron-rich nuclei have been performed within a prompt γ-ray spectroscopy experimental campaign. We report on results obtained from the cold-neutron induced fission of 235U. The excited secondary fission products were stopped almost instantaneously within the thick target and the γ rays emitted were collected triggerlessly using the EXILL&FATIMA mixed array of HPGe and LaBr3(Ce) detectors. Precise lifetimes could be determined by analysing the γ-γ time difference spectra using the generalized centroid difference method. This picosecondsensitive method provides many advantages and is briefly explained. Still, the major source of systematic errors is related to the contribution of time-correlated Compton background. The EXILL&FATIMA results are discussed with respect to the typical energy-dependent timing behaviour of the background. According to the time response of the background, appropriate methods and a time correction for the sub-nanosecond regime are proposed.
Published: 2017
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31. Spectroscopy of neutron-rich $^{194,96}$Y isotope produced in fission induced by cold neutrons

Author: Iskra, L.W., Fornal, B., Leoni, S., Bocchi, G., Blanc, A., Bottoni, S., Cieplicka-Oryńczak, N., Jentschel, M., Köster, U., Michelagnoli, C., Mutti, P., Soldner, T., De France, G., Simpson, G.S., Ur, C.A., Urban, W., Polish Academy of Sciences (PAN), Istituto Nazionale di Fisica Nucleare, Sezione di Milano (INFN), Istituto Nazionale di Fisica Nucleare (INFN), Institut Laue-Langevin (ILL), 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 Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Istituto Nazionale di Fisica Nucleare, Sezione di Padova (INFN, Sezione di Padova), Warsaw University of Technology [Warsaw], Vernay, Emmanuelle, ILL, 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), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract: International audience; The onset of the deformation in neutron-rich nuclei around A = 100 mass region has for many years remainedone of the most interesting subjects for nuclear spectroscopy study. For the neutron number N = 60, a sudden onsetof the deformation has been observed at the ground state, which is manifested by the presence of rotational bands(e.g. [1]). On the other hand the occurrence of shape coexistence in nuclei with N = 58 and 59, in this region (e.g.[2]), suggests that the evolution of the deformation is a more gradual process. In the yttrium isotopic chain, arotational band above the 4-, 496-keV isomer has been observed in the N = 59, 98Y nucleus, while there was noevidence of the deformed structure in the Y isotopes with neutron number less than N = 59. Our goal was toinvestigate N = 57, 96Y isotope where only a few states were known from beta decay study of 96Sr [3] as well as thelong 9.6-s (1140-keV) isomer [4]. Additionally, we decided to investigate whether deformed structures are stillpresent in the 94Y nucleus which lies 5 neutrons away from the N=60 boundary. So far, very little spectroscopicinformation has been gathered on 94Y – what regards higher spin yrast excitations established was only the presenceof the 1.35-μs, (5+) isomer at 1202 keV excitation energy [5]. This isomer could be used as a starting point for theidentification of structures on top of it.The yttrium-94 and 96 isotopes have been produced by fission of 235U and 241Pu targets induced by coldneutron from the reactor at Institut Laue-Langevin. The level scheme up to excitation energies in excess of 5 MeVhas been established based on multi-fold gamma-ray coincidence relationships measured with the EXILLspectrometer [6] which consists of up to 46 HPGe detectors. By exploiting delayed- and cross-coincidencetechniques, extensive structure has been delineated. During the analysis, over 50 new gamma transitions which feedpreviously known low-spin states as well as the long 9.6-s, 8+ isomer in 96Y isotope have been identified. Moreover,a new isomeric state at 1655-keV excitation energy has been located with half-life of 201 ns. Angular correlationanalysis allows to define spin-parity assignment for most of the identified levels, in particular (6+) for new isomer.By using the delayed-coincidence method it was possible to identify above the 201-ns state a few weak transitions,which seem to form a rotational band, in analogy to the structure above the 4- isomer in the 98Y isotope. In the caseof 94Y isotope over 11 new gamma transitions, which feed the previously known (5+) isomer, have been identified.Angular correlation analysis supported by shell-model consideration allowed to propose spin-parity assignmentsfor some of the new levels.The existence of the new isomeric state and the possible deformed band built on that isomer in the N = 57, 96Yisotope shed new light on the study of the onset of deformation in neutron-rich nuclei around N = 60. It shows thatthe deformed structures appear just after the subshell closure at N = 56 and evolve smoothly when passing throughN = 57-59 isotopes, to became a ground state structure in the 99Y isotope, i.e., at N = 60. The findings are in linewith the 94Y results where only spherical structures are present at low excitation energy.
Published: 2017

32. Ultra high precision refractive index measurement of Si at $\gamma$-ray energies up to 2 MeV

Author: Günther, M. M., Jentschel, M., Pollitt, A. J., Thirolf, P. G., and Zepf, M.
Subjects: Physics - Instrumentation and Detectors, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Physics::Optics, Physics - Atomic Physics
Abstract: The refractive index of silicon at $\gamma$-ray energies from 181 - 1959 keV was investigated using the GAMS6 double crystal spectrometer and found to follow the predictions of the classical scattering model. This is in contrast to earlier measurements on the GAMS5 spectrometer, which suggested a sign-change in the refractive index for photon energies above 500 keV. We present a re-evaluation of the original data from 2011 as well as data from a 2013 campaign in which we show that systematic errors due to diffraction effects of the prism can explain the earlier data., Comment: submitted to Physical Review C
Published: 2017

33. Half-life of the 15/2(+) state of I-135: A test of E2 seniority relations

Author: Spagnoletti, P, Simpson, GS, Carroll, R, Regis, J-M, Blanc, A, Jentschel, M, Koster, U, Mutti, P, Soldner, T, de France, G, Ur, CA, Urban, W, Bruce, AM, Drouet, F, Fraile, LM, Gaffney, LP, Ghita, DG, Ilieva, S, Jolie, J, Korten, W, Kroell, T, Larijarni, C, Lalkovski, S, Lica, R, Mach, H, Marginean, N, Paziy, V, Podolyak, Zs, Regan, PH, Scheck, M, Saed-Samii, N, Thiamova, G, Townsley, C, Vancraeyenest, A, Vedia, V, Gargano, A, and Van Isacker, P
Published: 2017

34. Abrupt shape transition at neutron number N = 60 : B ( E 2 ) values in $^{ 94 , 96 , 98}$Sr from fast $\gamma − \gamma$ timing

Author: Régis, M., Jolie, J., Saed-Samii, N., Warr, N., Pfeiffer, M., Blanc, A., Jentschel, M., Köster, U., Mutti, P., Soldner, T., Simpson, G.S., Drouet, F., Vancraeyenest, A., De France, G., Clément, E., Stezowski, O., Ur, A., Urban, W., Regan, H., Podolyák, Zs., Larijani, C., Townsley, C., Carroll, R., Wilson, E., Fraile, M., Mach, H., Paziy, V., Olaizola, B., Vedia, V., Bruce, A., Roberts, O. J., Smith, J. F., Scheck, M., Kröll, T., Hartig, A., Ignatov, A., Ilieva, S., Lalkovski, S., Korten, W., Mărginean, N., Otsuka, T., Shimizu, N., Togashi, T., Tsunoda, Y., Institut Laue-Langevin (ILL), ILL, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), 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 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), 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 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 Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract: International audience; Lifetimes of low-lying yrast states in neutron-rich 94,96,98Sr have been measured by Germanium-gated γ−γ fast timing with LaBr3(Ce) detectors using the EXILL&FATIMA spectrometer at the Institut Laue-Langevin. Sr fission products were generated using cold-neutron-induced fission of 235U and stopped almost instantaneously within the thick target. The experimental B(E2) values are compared with results of Monte Carlo shell-model calculations made without truncation on the occupation numbers of the orbits spanned by eight proton and eight neutron orbits and show good agreement. Similarly to the Zr isotopes, the abrupt shape transition in the Sr isotopes near neutron number N=60 is identified as being caused by many-proton excitations to its g9/2 orbit.
Published: 2017
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35. Shape coexistence in the odd-odd nucleus $^{98}\mathrm{Y}$: The role of the ${g}_{9/2}$ neutron extruder

Author: Urban, W., Czerwiński, M., Kurpeta, J., Rząca-Urban, T., Wiśniewski, J., Materna, T., Iskra, Ł. W., Smith, A.G., Ahmad, I., Blanc, A., Faust, H., Köster, U., Jentschel, M., Mutti, P., Soldner, T., Simpson, G.S., Pinston, J.A., De France, G., Ur, C.A., Elomaa, V.V., Eronen, T., Hakala, J., Jokinen, A., Kankainen, A., Moore, I.D., Rissanen, J., Saastamoinen, A., Szerypo, J., Weber, C., Äystö, J., 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 Laue-Langevin (ILL), ILL, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), 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), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), 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 Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract: International audience; Excited states in $^{98}$Y, populated in neutron-induced fission of U$^{235}$ and in spontaneous fission of $^{248}$Cm and $^{252}$Cf, have been studied by means of $\gamma$ spectroscopy using the Lohengrin fission-fragment separator at ILL Grenoble and the EXILL, Eurogam2, and Gammasphere Ge arrays. Two new isomers have been found in $^{98}$Y: a deformed one with T$_{1/2}$=180(7) ns and a rotational band on top of it, and a spherical one with T$_{1/2}$=0.45(15)μs, analogous to the 8$^+$ isomer in $^{96}$Y, corresponding to the (νg7/2,πg$_{9/2}$)8$^+$ spherical configuration. Using the JYFLTRAP Penning trap, an accurate excitation energy of 465.7(7) keV has been determined for the 2.36-s isomer in $^{98}$Y. This result and the studies of excited levels in $^{98}$Zr, populated in β$^−$ decay of the isomer, indicate a new spin-parity, Iπ=(7)$^+$ for the isomer. The high spin and the decay properties of this isomer suggest the presence of the 9/2$^+$[404] neutron extruder orbital in its structure. This is consistent with the large deformation of the isomer, reported recently. The present work does not provide arguments to support the special role of the νg7/2-πg$_{9/2}$ interaction (the spin-orbit-partner, or SOP, mechanism).
Published: 2017
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36. Structure of $^{90,91}$Kr nuclei: Solving the puzzle of their population in fission

Author: Rząca-Urban, T., Sieja, K., Urban, W., Czerwiński, M., Blanc, A., Jentschel, M., Mutti, P., Köster, U., Soldner, T., De France, G., Simpson, G.S., Ur, C.A., Institut Laue-Langevin (ILL), ILL, 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 Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), 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 National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)
Subjects: [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract: International audience; Excited states of $^{90,91}$Kr nuclei have been populated following the cold-neutron-induced fission of a $^{235}$U target. The γ rays emitted following fission reactions were measured using the highly efficient array of high-purity Ge detectors, EXILL, at the Institute-Laue-Langevin, Grenoble. The surprisingly low population of $^{91}$Kr reported in the spontaneous fission of $^{252}$Cf measurement has been explained and new level schemes of $^{90,91}$Kr nuclei were established. Moderate γ collectivity is observed in both nuclei. Large-scale shell-model calculations support the experimental picture of the Z=36, Kr isotopes forming a border line between lower-Z nuclei showing moderate γ collectivity and the heavier-Z nuclei, where distinct shape changes are observed.
Published: 2017
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37. EXILL - a high efficiency, high resolution setup for γ-spectroscopy at an intense cold neutron beam

Author: Jentschel, M., Blanca, A., France, G., Köster, U., Leoni, S., Mutti, P., Simpson, G., Soldner, T., Ur, C., Urban, W., Ahmed, S., Astieri, A., Augey, L., Back, T., Baczyk, P., Bajoga, A., Balabanski, D., Belgya, T., Benzoni, G., Bernards, C., Biswas, D., Bocchi, G., Bottoni, S., Britton, R., Bruyneel, B., Burnett, J., Cakirli, R. B., Carroll, R., Catford, W., Cederwall, B., Celikovic, I., Cieplicka, N., Clement, E., Cooper, N., Crespic, F., Csatlos, M., Czerwinski, M., Danu, L., Davies, A., Didierjean, F., Drouet, F., Duchene, G., Ducoin, C., Eberhardt, K., Erturk, S., Fraile, L. M., Gottardo, A., Grente, L., Grocutt, L., Guerrero, C., Guinet, D., Hartig, A.-L., Henrich, C., Ignatov, A., Ilieva, S., Ivanova, D., John, B., John, R., Jolie, J., Kisyov, S., Konstantinopoulos, T., Korgul, A., Krasznahorkay, A., Kröll, T., Kurpeta, J., Kutiu, I., Lalkovski, S., Larijani, C., Leguillon, R., Lica, R., Litaize, O., Magron, C., Mancuso, C., Ruiz Martinez, E., Massarczyk, R., Mazzocchi, C., Melon, B., Mengoni, D., Million, B., Mokry, C., Mukhopadhyay, S., Mulholland, K., Nannini, A., Napoli, D. R., Olaizola, B., Orlandi, R., Patel, Z., Paziy, V., Petrache, C., Pfeiffer, M., Podolyak, Z., Ramdhane, M., Redon, N., Regan, P., Regis, J. M., Regnier, D., Oliver, R. J., Rudigier, M., Runke, J., Rzaca-Urban, T., Saed-Samii, N., Salsacq, M. D., Scheck, M., Schwengner, R., Sengele, L., Singh, P., Smith, J., Stezowski, O., Szpak, B., Thomas, T., Thürauf, M., Timaru, J., Toml, A., Tomandl, I., Tornyi, T., Townsley, C., Tuerler, A., Valenta, S., Vancraeyenest, A., Vandone, V., Vanhoy, J., Vedia, V., Warr, N., Werner, V., Wilmsen, D., Wilson, E., Zerrouki, T., and Zielinska, M.
Subjects: 235U, Ge detectors, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, neutron-induced fission, multiple-γ coincidences, (n,γ)-reactions, 241Pu, angular correlations
Abstract: In the EXILL campaign a highly efficient array of HPGe detectors was operated at the cold neutron beam instrument PF1B of the Institut Laue-Langevin to carry out nuclear structure studies, via measurements of -rays following neutron-induced capture and fission reactions. The setup consisted of a collimation system producing a pencil beam with a thermal capture equivalent flux of about 108 s-1 cm-2 at the target position and negligible neutron halo. The target was surrounded by an array of eight to ten anti-Compton shielded EXOGAM clover detectors, four to six anti-Compton shielded large coaxial GASP detectors and two smaller clover detectors. The detectors were arranged in an array of rhombicuboctahedron geometry, providing the possibility to carry out very precise angular correlation and directional-polarization correlation measurements. The trigger-less acquisition system allowed an event collection rate of up to 6 × 105 Hz. From triggerless collected data it was possible to construct decay schemes and in combination with the FATIMA array of LaBr3 detectors to analyze half-lives of excited levels in the pico- to micro-second range. Precise energy and efficiency calibrations of EXILL were performed using 27Al(n,γ)28Al and 35Cl(n,γ)36Cl reactions in the energy range from 30 keV up to 10 MeV.
Published: 2017

38. Ultra high precision refractive index measurement of Si at $��$-ray energies up to 2 MeV

Author: G��nther, M. M., Jentschel, M., Pollitt, A. J., Thirolf, P. G., and Zepf, M.
Subjects: Physics::Instrumentation and Detectors, Atomic Physics (physics.atom-ph), Astrophysics::High Energy Astrophysical Phenomena, Physics::Optics, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det)
Abstract: The refractive index of silicon at $��$-ray energies from 181 - 1959 keV was investigated using the GAMS6 double crystal spectrometer and found to follow the predictions of the classical scattering model. This is in contrast to earlier measurements on the GAMS5 spectrometer, which suggested a sign-change in the refractive index for photon energies above 500 keV. We present a re-evaluation of the original data from 2011 as well as data from a 2013 campaign in which we show that systematic errors due to diffraction effects of the prism can explain the earlier data., submitted to Physical Review C
Published: 2017
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39. Lifetime measurements in $^{162}$Dy

Author: Aprahamian, A., Lesher, S.R., Casarella, C., Börner, H.G., Jentschel, M., Institut Laue-Langevin (ILL), and ILL
Subjects: [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract: International audience; Background: The nature of oscillations or excitations around the equilibrium deformed nuclear shape remains an open question in nuclear structure. The Dy162 nucleus is one of the most extensively studied nuclei with the (n,γ), (n,e−), (α,2n) reactions and most recently the (p,t) pickup reaction adding 11 0+ states to an excitation energy of 2.8 MeV to an already-well-developed level scheme. However, a major shortfall for a better understanding of the nature of the plethora of bands and levels in this nucleus has been the lack of lifetime measurements. Purpose: To determine the character of the low-lying excited bands in this Dy162 nucleus, we set out to measure the level lifetimes. Method: Lifetimes were measured in the Dy162 nucleus following neutron capture using the Gamma-Ray-Induced Doppler (GRID) broadening technique at the Institut Laue-Langevin in Grenoble, France. Results: In total, we have measured the lifetimes of 12 levels belonging to a number of excited positive- and negative-parity bands in the low-lying spectrum of the Dy162 nucleus. The lifetime of the Kπ=2+ bandhead at 888.16 keV was previously measured. We confirm this value and measure lifetimes of the 3+ and 4+ members of this band yielding B(E2) values that are consistent with a single γ-vibrational phonon of several Weisskopf units. The first excited Kπ=4+ band, with a bandhead at 1535.66 keV, is strongly connected to the Kπ=2+ band with enhanced collective B(E2) values and it is consistent with a double phonon vibrational (γγ) excitation. Lifetime of Kπ=0+ band members have also been measured, including the 4Kπ=02++ state at 1574.29 keV and the 2Kπ=03++ state at 1728.31 keV. This latter state also displays the characteristics of a double phonon excitation built on the Kπ=2+ band. Conclusions: We discuss our findings in terms of the presence or absence of collective quadrupole and octupole vibrational excitations. We find two positive-parity excited bands at 1535.66 keV (Kπ=4+) and the 1728.312-keV 2+ state of a Kπ=0+ band at 1666 keV connected with sizably collective B(E2) values to the (Kπ=2+)γ band at 888 keV.
Published: 2017
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40. Experimental study of the lifetime and phase transition in neutron-rich $^{98,100,102}\mathrm{Zr}$

Author: Ansari, S, Régis, J.-M., Jolie, J., Saed-Samii, N., Warr, N., Korten, W., Zielinska, M., Salsac, M.-D., Blanc, A., Jentschel, M., Köster, U., Mutti, P., Soldner, T., Simpson, G.S., Drouet, F., Vancraeyenest, A., de France, G., Clément, E., Stezowski, O., Ur, C.A., Urban, W., Regan, P.H., Podolyák, Zs., Larijani, C., Townsley, C., Carroll, R., Wilson, E., Mach, H., Fraile, L.M., Paziy, V., Olaizola, B., Vedia, V., Bruce, A.M., Roberts, O.J., Smith, J.F., Scheck, M., Kröll, T., Hartig, A.-L., Ignatov, A., Ilieva, S., Lalkovski, S., Marginean, N., Otsuka, T., Shimizu, N., Togashi, T., Tsunoda, Y., 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 Laue-Langevin (ILL), ILL, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), 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 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), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), 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 Claude Bernard Lyon 1 (UCBL), 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), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract: International audience; Rapid shape changes are observed for neutron-rich nuclei with A around 100. In particular, a sudden onset of ground-state deformation is observed in the Zr and Sr isotopic chains at N = 60: Low-lying states in N 58 nuclei are nearly spherical, while those with N 60 have a rotational character. Nuclear lifetimes as short as a few picoseconds can be measured using fast-timing techniques with LaBr3(Ce) scintillators, yielding a key ingredient in the systematic study of the shape evolution in this region.We used neutron-induced fission of 241Pu and 235U to study lifetimes of excited states in fission fragments in the A ∼ 100 region with the EXILL-FATIMA array located at the PF1B cold neutron beam line at the Institut Laue-Langevin. In particular, we applied the generalized centroid difference method to deduce lifetimes of low-lying states for the nuclei 98Zr (N = 58), 100Zr,and 102Zr (N 60). The results are discussed in the context of the presumed phase transition in the Zr chain by comparing the experimental transition strengths with the theoretical calculations using the interacting boson model and the Monte Carlo shell model.
Published: 2017
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41. Shape coexistence in the odd-odd nucleus 98Y : the role of the g9/2 neutron extruder

Author: Urban, W., Czerwinski, M., Kurpeta, J., Rzaca-Urban, T., Wisniewski, J., Materna, T., Iskra, L. W., Smith, A. G., Ahmad, I., Blanc, A., Faust, H., Köster, U., Jentschel, M., Mutti, P., Soldner, T., Simpson, G. S., Pinston, J. A., France, G. de, Ur, C. A., Elomaa, Viki-Veikko, Eronen, Tommi, Hakala, Jani, Jokinen, Ari, Kankainen, Anu, Moore, Iain, Rissanen, Juho, Saastamoinen, Antti, Szerypo, Jerzy, Weber, Christine, and Äystö, Juha
Subjects: level densities, leveys, lifetimes, energy levels, isomer decays, nuclear structure and decayss
Abstract: Excited states in 98Y, populated in neutron-induced fission of 235U and in spontaneous fission of 248Cm and 252Cf, have been studied by means of γ spectroscopy using the Lohengrin fission-fragment separator at ILL Grenoble and the EXILL, Eurogam2, and Gammasphere Ge arrays. Two new isomers have been found in 98Y: a deformed one with T1/2 = 180(7) ns and a rotational band on top of it, and a spherical one with T1/2 = 0.45(15)μs, analogous to the 8+ isomer in 96Y, corresponding to the (νg7/2,πg9/2)8+ spherical configuration. Using the JYFLTRAP Penning trap, an accurate excitation energy of 465.7(7) keV has been determined for the 2.36-s isomer in 98Y. This result and the studies of excited levels in 98Zr, populated in β− decay of the isomer, indicate a new spin-parity, I π = (7)+ for the isomer. The high spin and the decay properties of this isomer suggest the presence of the 9/2+[404] neutron extruder orbital in its structure. This is consistent with the large deformation of the isomer, reported recently. The present work does not provide arguments to support the special role of the νg7/2 - πg9/2 interaction (the spin-orbit-partner, or SOP, mechanism). peerReviewed
Published: 2017

42. Half-life of the 15/2$^+$ state of $^{135}$I : A test of E2 seniority relations

Author: Spagnoletti, P., Simpson, G.S., Carroll, R., Régis, M., Blanc, A., Jentschel, M., Köster, U., Mutti, P., Soldner, T., De France, G., Ur, A., Urban, W., Bruce, A., Drouet, F., Fraile, M., Gaffney, P., Ghită, G., Ilieva, S., Jolie, J., Korten, W., Kröll, T., Larijarni, C., Lalkovski, S., Lică, R., Mach, H., Mărginean, N., Paziy, V., Podolyák, Zs., Regan, P., Scheck, M., Saed-Samii, N., Thiamova, G., Townsley, C., Vancraeyenest, A., Vedia, V., Gargano, A., Van Isacker, P., Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut Laue-Langevin (ILL), 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), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, ILL, 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: [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract: International audience; The half-life of the 15/2+1 state of the 3-valence-proton nucleus 135I has been measured to be 1.74(8) ns using the EXILL-FATIMA mixed array of Ge and LaBr3 detectors. The nuclei were produced following the cold neutron-induced fission of a 235U target at the PF1B beam line of the Institut Laue-Langevin. The extracted B(E2;15/2+→11/2+) value enabled a test of seniority relations for the first time between E2 transition rates. Large-scale shell-model calculations were performed for 134Te and 135I, and reinterpreted in a single-orbit approach. The results show that the two-body component of the E2 operator can be large whereas energy shifts due to the three-body component of the effective interaction are small.
Published: 2017
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43. EXILL - a high-efficiency, high-resolution setup for gamma-spectroscopy at an intense cold neutron beam facility

Author: Jentschel, M., Blanc, A., de France, G., Koster, U., Leoni, S., Mutti, P., Back, T., and 0-Belirlenecek
Subjects: Instrumentation for neutron sources, Spectrometers, Gamma detectors (scintillators, CZT, HPG, HgI etc)
Abstract: WOS: 000414625700003, In the EXILL campaign a highly efficient array of high purity germanium (HPGe) detectors was operated at the cold neutron beam facility PF1B of the Institut Laue-Langevin (ILL) to carry out nuclear structure studies, via measurements of gamma-rays following neutron-induced capture and fission reactions. The setup consisted of a collimation system producing a pencil beam with a thermal capture equivalent flux of about 10(8) ns(-1)cm(2) at the target position and negligible neutron halo. The targetwas surrounded by an array of eight to ten anti-Compton shielded EXOGAMClover detectors, four to six anti-Compton shielded large coaxial GASP detectors and two standard Clover detectors. For a part of the campaign the array was combined with 16 LaBr3:(Ce) detectors from the FATIMA collaboration. The detectorswere arranged in an array of rhombicuboctahedron geometry, providing the possibility to carry out very precise angular correlation and directional-polarization correlation measurements. The triggerless acquisition system allowed a signal collection rate of up to 6 x 10(5) Hz. The data allowed to set multi-fold coincidences to obtain decay schemes and in combination with the FATIMA array of LaBr3:(Ce) detectors to analyze half-lives of excited levels in the pico-to microsecond range. Precise energy and efficiency calibrations of EXILL were performed using standard calibration sources of Ba-133, Co-60 and Eu-152 as well as data from the reactions Al-27(n, gamma)Al-28 and Cl-35(n,gamma)Cl-36 in the energy range from 30 keV up to 10MeV., U.S. DOE grant [DE-FG02-91ER40609]; NUPNET; German BMBF [O5P12PKNUF, 05P15RDFN1, 05P12RDNUP]; German DFG contract [KR 1796/2-1]; Polish National Science Centre [DEC-2013/09/B/ST2/03485], This work has been partly supported by the Polish National Science Centre under contract DEC-2013/09/B/ST2/03485, the U.S. DOE grant No. DE-FG02-91ER40609, the NUPNET and the German BMBF under contracts O5P12PKNUF, 05P15RDFN1 and 05P12RDNUP and the German DFG contract KR 1796/2-1.
Published: 2017

44. Excited 0$^+$ states and deformed structures in the transitional nucleus $^{98}$Zr

Author: Mukhopadhyay, S., Biswas, D.C., Danu, L.S., Kumawat, A.K., Singh, Abhilasha, Blanc, A., De France, G., Jentschel, M., Koster, U., Leoni, S., Mutti, P., Simpson, G., Soldner, T., Ur, C.A., Urban, W., Institut Laue-Langevin (ILL), 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 Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Vernay, Emmanuelle, ILL, 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), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.NUCL] Physics [physics]/Nuclear Theory [nucl-th], [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2016

45. Medium and High Spin Structure in the $^{94}$Y Isotope Produced in Fission Induced by Cold Neutrons

Author: Iskra, L.W., Fornal, B., Leoni, S., Bocchi, G., Jentschel, M., Köster, U., Mutti, P., Soldner, T., Blanc, A., De France, G., Régis, J.M., Simpson, G.S., Urban, W., Ur, C.A., Institut Laue-Langevin (ILL), 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 Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), ILL, 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 National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS), and Lion, Michel
Subjects: [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract: International audience; The shape of a particular nucleus results from an interplay between the collective (macroscopic)and single-particle (microscopic) energies and, therefore, highly depends on both the atomicnumber Z and the neutron number N. The neutron-rich nuclei around Z=40 and N=60 provide oneof the best territories for the exploration of this sensitivity. Indeed, the sudden onset ofdeformation observed for neutron-rich nuclei with Z = 36–40 nuclei near N=60 is considered themost dramatic shape change in the nuclear chart. Nevertheless, the resent study of the yttriumisotopic chain reveal occurrence of shape coexistence in the 98Y isotope [1] and possible rotationalband above the 6- isomeric state in the 96Y nucleus [2]. This suggests that the evolution of thedeformation is a more gradual process. Therefore, we decided to investigate whether deformedstructures are still present in the 94Y nucleus which lies 5 neutrons away from the N=60 boundary.So far, very little spectroscopic information has been gathered on 94Y – what regards higher spinyrast excitations established was only the presence of the 1.35-μs, (5+) isomer at 1202 keVexcitation energy [3]. This isomer could be used as a starting point for the identification ofstructures on top of it.The 94Y isotope has been produced by fission of 235U target induced by cold neutron from thereactor at Institut Laue-Langevin. The level scheme up to excitation energies of about 7 MeV hasbeen established based on multi-fold gamma-ray coincidence relationships measured with theEXILL spectrometer [4] which consists of up to 46 HPGe detectors. During the analysis, over 30 newgamma transitions, which feed the previously known (5+) isomer, have been identified. Angularcorrelation analysis allows to define spin-parity assignment for most of the identified levels. Theidentified transitions don’t show any pattern characteristic for deformed structures. Furthermore,no higher located isomer has been found, similar to the ones known in heavier yttrium isotopes onwhich the rotational bands are built. Those findings are in line with the expectations that in 94Y onlyspherical structures are present at low excitation energy.[1] S. Brant, G. Lhersonneau, and K. Sistemich, Phys. Rev. C 69, 034327 (2004)[2] Ł. W. Iskra et al., to be published[3] J. Genevey et al., Phys. Rev. C 59, 82 (1999)[4] M. Jentschel et al., EXILL technical paper, JINST (subm. 2015)
Published: 2016

46. Lifetimes of the 2$^+_1$ and the 4$^+_1$ States of $^{148}$Ce and its B$_{4/2}$ Ratio from EXILL&FATIMA Experiment

Author: Koseoglou, P., Werner, V., Pietralla, N., Ilieva, S., Bernards, C., Blanc, A., Bruce, A.M., Cakirli, R.B., Cooper, N., de France, G., Jentschel, M., Jolie, J., Koester, U., Kröll, T., Mutti, P., Patel, Z., Paziy, V., Podolyak, Zs., Regan, P.H., Regis, J.M., Roberts, O.J., Saed-Samii, N., Simpson, G.S., Soldner, T., Ur, C.A., Urban, W., Wilmsen, D., Wilson, E., Institut Laue-Langevin (ILL), ILL, 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), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS), Lion, Michel, 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 Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract: International audience; The even-even N=90 isotones with Z=60-66, present an interesting phase transition. This phasetransition in nuclei is characterized by a sudden change of the shape of the nucleus [1]. 148Ce lies onthe downboundaries of the phase transition region and therefore further elucidate the underlyingmechanisms that lend the shape phase transition behavior. 235U and 241Pu fission fragments were measured by a mixed spectrometer consisting of highresolution Ge and fast LaBr3(Ce)-scintillator detectors at the high-flux reactor of the ILL. Prompt γ-ray cascades from the nuclei of interest are selected via Ge-Ge-LaBr3-LaBr3 coincidences. The goodenergy resolution of the Ge allows precise gates to be set, selecting the cascade, hence, the nucleusof interest. The excellent timing performance of the LaBr3 detectors in combination with theGeneral Centroid Difference method [2] allows the measurement of lifetimes in the ps range inpreparation for the FATIMA experiment at FAIR. The first results on neutron-rich 148Ce arepresented.
Published: 2016

47. Low-spin structure of $^{86}_{35}$Br$_{51}$ and $^{86}_{36}$Kr$_{50}$ nuclei: The role of the g $_{7/2}$ neutron orbital

Author: Urban, W., Sieja, K., Materna, T., Czerwinski, M., Rzaca-Urban, T., Blanc, A., Jentschel, M., Mutti, P., Köster, U., Soldner, T., de France, G., Simpson, G. S., Ur, C., Bernards, C., Fransen, C., Jolie, J., Regis, J.-M., Thomas, T., Warr, N., 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), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Laue-Langevin (ILL), ILL, 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), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), 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 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)
Subjects: [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract: International audience; Low-spin excited levels in Br513586 and Kr503686, populated following β− decay and the neutron-induced fission of U235, were measured using the Lohengrin fission-fragment separator and the EXILL array of Ge detectors at the PF1B cold-neutron facility of the Institute Laue-Langevin Grenoble. Improved populations of excited levels in Br86 remove inconsistencies existing in the literature on this nucleus. Directional-linear-polarization correlations, analyzed using newly developed formulas, as well as precise angular correlations allowed the unique 1− and 2− spin and parity assignments to the ground state of Br86 and the 4016.3-keV level in Kr86, respectively. Based on these results we propose that the Gamow-Teller β− decays of Se86 and Br86 involve the νg7/2→πg9/2 transition in addition to the νp3/2→πp3/2 transition proposed earlier. In Kr86 we have identified 1+1, 2+3, and 3+1 levels, analogous to the mixed-symmetry states in Mo94, which in Kr86 are from proton excitations, only. Large-scale, shell-model calculations with refined interactions reproduce well excitations in Br86 and Kr86 and support our interpretations.
Published: 2016
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48. Multipolarity of the 2− → 1−, ground-state transition in $^{210}$Bi via multivariable angular correlation analysis

Author: Cieplicka-Oryńczak, N., Szpak, B., Leoni, S., Fornal, B., Bazzacco, D., Blanc, A., Bocchi, G., Bottoni, S., de France, G., Jentschel, M., Köster, U., Mutti, P., Simpson, G., Soldner, T., Ur, C., Urban, W., Institut Laue-Langevin (ILL), ILL, 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), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), EXILL, and 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)
Subjects: [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract: International audience; The multipolarity of the main transition leading to the ground state in 210Bi was investigated using the angularcorrelations of γ rays. The analyzed γ -coincidence data were obtained from the 209Bi(n,γ )210Bi experimentperformed at Institut Laue-Langevin Grenoble at the PF1B cold-neutron facility. The EXILL (EXOGAM at theILL) multidetector array, consisting of 16 high-purity germanium detectors, was used to detect γ transitions. Themixing ratio of the 320-keV γ ray was defined by minimizing a multivariable χ2 function constructed from thecoefficients of angular correlation functions for seven pairs of strong transitions in 210Bi. As a result, the almostpure M1 multipolarity of the 320-keV γ ray was obtained, with an E2 admixture of less than 0.6% only (95%confidence limit). Based on this multipolarity the neutron-capture cross section leading to the ground state in210Bi, that decays in turn to radiotoxic 210Po, was determined to be within the limits 21.3(9) and 21.5(9) mb. Thisresult is important for nuclear reactor applications.
Published: 2016
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49. Approaching complete low-spin spectroscopy of $^{210}$Bi with a cold-neutron capture reaction

Author: Cieplicka-Oryńczak, N., Fornal, B., Leoni, S., Bazzacco, D., Blanc, A., Bocchi, G., Bottoni, S., De France, G., Jentschel, M., Köster, U., Mutti, P., Simpson, G., Soldner, T., Szpak, B., Ur, C., Urban, W., Institut Laue-Langevin (ILL), 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 Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), EXILL, ILL, 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: EXOGAM, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, EXILL
Abstract: The experiment was performed at the PF1B cold-neutron facility at the Institut Laue-Langevin in Grenoble (France); International audience; The low-spin structure of the 210Bi nucleus was investigated in the neutron capture experiment 209Bi(n,γ )210Biperformed at ILL Grenoble at the PF1B cold-neutron facility. By using the EXILL multidetector array, consistingof 46 high-purity germanium crystals, and γγ-coincidence technique, 64 primary γ rays were observed (40new) and a total number of 70 discrete states (33 new) were located below the neutron binding energy in 210Bi.The analysis of the angular correlations of γ rays provided information about transitions multipolarities, whichmade it possible to confirm most of the previously known spin-parity assignments and helped establish new ones.The obtained experimental results were compared to shell-model calculations involving one-valence-proton,one-valence-neutron excitations outside the 208Pb core. It has been found that while up to the energy of ∼2 MeVeach state observed in 210Bi has its calculated counterpart; at higher excitation energies some levels cannot bedescribed by the valence particle couplings. These states may arise from couplings of valence particles to the 3−octupole phonon of the doubly magic 208Pb core and may serve as a testing ground for models which describesingle particle-phonon excitations.
Published: 2016
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50. Preface

Author: Degenkolb S., Geltenbort P., Jenke (Workshop Chair) T., Jentschel M., Nesvizhevsky V.V., Roccia S., Soldner T., Zimmer O., Rebreyend D., and Stutz A.
Subjects: Physics, QC1-999
Abstract: This volume contains the written proceedings of PPNS-2018, the international workshop on “Particle Physics at Neutron Sources” hosted by the LPSC in Grenoble, France from May 24th–26th, 2018.
Published: 2019
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